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Living by Chemistry (LBC) is a full-year high school curriculum that incorporates science practices with a guided-inquiry approach. LBC's innovative curriculum offers much more than traditional programs. To help engage students of all levels, the curriculum provides a variety of learning experiences through text, activities, discussions, games, demos, lectures, labs, and individual work.

To fully implement the LBC program student textbooks must be ordered. NYC DOE Schools can use ShopDOE item number: 902314432 to order student textbooks. The complete set of teacher and student resources will be provided complimentary with a class set purchase, including the Teacher's Resource Flash Drive, ExamView Test Bank, and Teacher's Edition textbook. These teacher resources are an essential part of the program.

Alternatively, you may order directly from Bedford, Freeman & Worth (BFW) by submitting a purchase order (PO) to your BFW sales representative or their processing warehouse. Schools may use this method to order hard copy textbooks as well as order access to BFW's digital platform, SaplingPlus, which includes online homework and an accessible, interactive e-book. Price quotes of class sets have free resources listed. Sample price quote for book and digital.

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Chemistry - New Visions Science Curriculum

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Living by Chemistry (LBC) is a full-year high school curriculum that incorporates science practices with a guided-inquiry approach. LBC's innovative curriculum offers much more than traditional programs. To help engage students of all levels, the curriculum provides a variety of learning experiences through text, activities, discussions, games, demos, lectures, labs, and individual work.

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A discussion of chemical hot and cold packs can really warm up a classroom lesson on thermochemistry. In the following activity, students use a coffee cup calorimeter to measure the heat of solution of a chemical salt using 3 different masses. It's recommended for safety-and for a more green chemistry experience-that students use ammonium chloride for the cold packs and calcium chloride for the hot packs. If chemicals are limited, consider having half the students work with 1 chemical and half with the other. After students have measured the heat of solution for the 3 masses, they graph their data (change in temperature vs. mass) and draw a best fit line. The best fit line can be used to determine what mass of chemical is needed to achieve a specific temperature. Students then design a hot and/or cold pack that utilizes 100 mL of water and can be activated when needed. Ensure that you review student designs before allowing them to perform the activity and that students understand and follow appropriate safety protocols.

Background

Calorimetry

Calorimetry is the science of measuring heat. Many chemical and physical transformations involve energy transfer in the form of heat. The magnitude and direction of heat may be determined using a calorimeter. In reactions that occur in aqueous solutions, the energy is transferred to or taken away from the water. A calorimeter is an apparatus that is insulated and prevents heat from flowing in or out of the system. Since the experiment is run under constant pressure (atmospheric), the change in water temperature that is measured is due to the enthalpy of reaction (heat of reaction). The heat of reaction may be calculated using the values measured for change in the water temperature.

The heat transfer, or change in enthalpy in a reaction (), is related to the mass of the solution ( m), the specific heat capacity of the solution (c), and the temperature change ().

The specific heat capacity of a substance is the amount of energy required to raise 1 g of the substance 1° C. The specific heat capacity of water is 4.186 J / (° C × g). In experiments conducted in aqueous solution, the specific heat capacity of water is generally used.

Instant Hot and Cold Packs

Many instant hot and cold packs function by dissolving a salt into water. As the salt disassociates, heat is either released in an exothermic reaction or absorbed in an endothermic reaction. Commercial instant cold packs typically use either ammonium nitrate or urea as their salt component; hot packs often use magnesium sulfate or calcium chloride. These reactions happen in a similar manner. When the salt is dissolved in water, the ionic bonds of the salt separate. This process requires energy, which is obtained from the surroundings. The ions then form bonds with the water, a process that releases energy. If more energy is released than taken in, then the process is exothermic, making the solution feel warmer. If more energy is taken in than released, then the process is endothermic, making the solution feel cooler.

Commercially, there are 2 other commonly sold types of instant hot packs. One heats up when exposed to air. This hot pack functions as iron reacts with oxygen to form iron (III) oxide, an exothermic reaction. The other type relies on the super cooling of sodium acetate. Upon heating the solution, it can become supersaturated. Without a seed crystal, the sodium acetate will remain in solution as it cools. This type of hot pack typically contains a metal disk that provides a site for crystallization when depressed. As the sodium acetate forms a regular crystal arrangement, heat is released. This hot pack is reusable as it can be regenerated in boiling water to once again form the supersaturated solution.

Safety

Use this activity only in accordance with established laboratory safety practices, including appropriate personal protective equipment (PPE) such as gloves, chemical splash goggles, and lab coats or aprons. Ensure that students understand and adhere to these practices. Know and follow all federal, state, and local regulations as well as school district guidelines for the disposal of laboratory wastes. Students should not eat, drink, or chew gum in the lab and should wash their hands before and after entering or exiting the lab.

Materials (per student group)

Calcium Chloride

Ammonium Chloride

3 Polystyrene Cups with Lids

Beaker, 400 mL

Beaker, 150 mL

Graduated Cylinder, 100 mL

Water

Thermometer

Hot Plate

Balance

Weigh Boats

Various Materials for Making Thermal Packs (as specified in the student designs)

Procedure

Activity 1

1. Place 1 polystyrene cup inside another and then place both cups inside a 400-mL beaker. This is your calorimeter for measuring changes in temperature.

2. Measure 100 mL of water with a graduated cylinder and pour it into the top polystyrene cup of the created calorimeter.

3. Place the lid on the calorimeter, pulling back the tab to form an opening. Insert a thermometer into the calorimeter through the opening in the lid.

4. Stir the water with the thermometer, monitoring the temperature until it is stable. Record this temperature (±0.1° C) as the initial temperature.

5. Measure 5 g of the chemical salt. Record the exact value used.

6. Remove the calorimeter lid, add the 5 g of chemical salt, and stir. Replace the lid and thermometer.

7. Continue to stir and monitor the temperature for 2 minutes. Record the highest or lowest temperature obtained (±0.1° C) as the final temperature.

8. Discard the solution as directed by your teacher and rinse the inner cup. Thoroughly dry the calorimeter apparatus before reusing.

9. Repeat steps 1 to 8 twice more with 10 g and 15 g of chemical salt, respectively.

10. Graph the change in temperature of chemical salt compared to the mass of chemical salt. Draw a best fit line for the points.

11. Optional data analysis: Calculate the heat absorbed by the water for each mass of the chemical salt and the heat absorbed by the calorimeter for each mass of chemical salt. The specific heat of water is 4.186 J/° C × g.

12. Calculate the enthalpy of the solution for each mass of chemical salt.

Activity 2

Design a portable, 1-time-use hot pack or cold pack for treating injuries. The pack must have 100 g of water separated from a solid chemical and be activated only when the user does something to the pack to mix the 2 components. Your job is to determine how many grams of the chemical are required to achieve the following temperatures: hot pack, 55° C (131° F); cold pack, 3° C (37° F).

The following is a guide for creating your thermal pack. Ensure that you understand how your teacher expects you to present your designs.

1. Diagram your hot or cold pack. Include labels to indicate sizes and quantities of materials used.

2. List all materials and quantities needed to create your thermal pack.

3. Explain the steps that you will follow to build your thermal pack.

4. Describe the safety precautions you will use when creating and testing the thermal pack.

5. Explain how you will test your hot or cold pack. Consider how you will know if you were successful.

6. Get approval from your instructor to construct your thermal pack.

7. Construct your thermal pack. Record any modifications that you make to your design during the construction phase.

8. Test your thermal pack. Record any data that you collect.

9. Explain whether your design was successful and what changes or modifications you would need to make if conducting this activity again.

Related products

*AP is a registered trademark of the College Board, which was not involved in the production of, and does not endorse, this product.

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hot and cold packs: a thermochemistry activity

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Hot and Cold Packs: A Thermochemistry Activity

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A discussion of chemical hot and cold packs can really warm up a classroom lesson on thermochemistry. In this hands-on activity, students use a coffee cup calorimeter to measure the heat of solution of a chemical salt using 3 different masses and then design their own hot and/or cold pack.

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Anyone watching the news knows healthcare is an ever-growing industry. So we head down to Macon to visit one of the area's largest employers: Coliseum Health System, where we learn that you don't have to be a doctor to be one of their 1,300+ employees! In fact, sometimes a high school education and a certificate or two are all you need to find a great job. On a different "note," we have a sing-along, hear an extremely moving story, and enjoy one of our weirdest Teachable Moments ever!

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Anyone watching the news knows healthcare is an ever-growing industry. So we head down to Macon to visit one of the area's largest employers: Coliseum Health System, where we learn that you don't have to be a doctor to be one of their 1,300+ employees!

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Citrus

The fertilization guidelines on this site have been redesigned to be compliant with AB434. The guidelines in the traditional design with the latest updates can be found on the UC Davis Nutrient Management website .

References

Nitrogen

1. Albrigo, L.G., 1999. Effects of foliar applications of urea or Nutri-Phite on flowering and yields of Valencia orange trees. Proceedings of the Florida State Horticultural Society 112, 1-4.

2. Albrigo, L.G., 2002. Foliar uptake of N-P-K sources and urea biuret tolerance in citrus. Acta Horticulturae 594, 627-633.

3. Ali, A.G., Lovatt, C.J., 1994. Winter application of low-biuret urea to the foliage of 'Washington' navel oranges increased yield. Journal of the American Society for Horticultural Science 119, 1144-1150.

4. Alva, A.K., Paramasivam, S., 1998. Nitrogen management for high yield and quality of citrus in sandy soils. Soil Science Society of America Journal 62, 1335-1342.

5. Alva, A.K., Paramasivam, S., Graham, W.D., Wheaton, T.A., 2003. Best nitrogen and irrigation management practices for citrus production in sandy soils. Water, Air, and Soil Pollution 143, 139-154.

6. Alva, A.K., Paramasivam, S., Obreza, T.A., Schumann, A.W., 2006. Nitrogen best management practice for citrus trees I. Fruit yield, quality, and leaf nutritional status. Scientia Horticulturae 107, 233-244.

7. Arpaia, M.L., Lund, L.J., 2003. Nitrogen management in citrus under low volume irrigation. FREP Final Report.

8. Bondada, B.R., Syvertsen, J.P., Albrigo, L.G., 2001. Urea nitrogen uptake by citrus leaves. HortScience 36, 1061-1065.

9. Cantarella, H., Mattos Jr., D., Quaggio, J.A., Rigolin, A.T., 2003. Fruit yield of Valencia sweet orange fertilized with different N sources and the loss of applied N. Nutrient Cycling in Agroecosystems 67, 215-223.

10. Chapman, H.D., 1968. The mineral nutrition of citrus. In: Reuther, W., Batchelor, L.D., Webber, H.J. (Eds.). The Citrus Industry, Volume II. University of California, Division of Agricultural Sciences. pp. 127-289.

11. Crowley, D., 2012. Macronutrients: Their role in citrus production. Presentation held at the California Citrus Conference, Porterville, October 10-11, 2012.

12. Dasberg, S., 1987. Nitrogen fertilization in citrus orchards. Plant and Soil 100, 1-9.

13. Embleton, T.W., Jones, W.W., 1974. Foliar-applied nitrogen for citrus fertilization. Journal of Environmental Quality 3, 388-391.

14. Embleton, T.W., Jones, W.W., Platt, R.G., Burns, R.M., 1974. Potassium nutrition and deficiency in citrus. California Agriculture 28(8), 6-8.

15. Embleton, T.W., Jones, W.W., Platt, R.G., 1976. Leaf analysis as a guide to citrus fertilization. In: Reisenauer, H.M. (Ed.). Soil and Plant-Tissue Testing in California. University of California Cooperative Extension Bulletin 1879. pp. 4-9.

16. Fake, C., 2004. Fertilizing citrus in the foothills. University of California Cooperative Extension Placer & Nevada Counties January 2004.

17. Feigenbaum, S., Bielorai, H., Erner, Y., Dasberg, S., 1987. The fate of ¹⁵N labeled nitrogen applied to mature citrus trees. Plant and Soil 97, 179-187.

18. He, Z.L., Calvert, D.V., Alva, A.K., Banks, D.J., Li, Y.C., 2003. Thresholds for leaf nitrogen in optimum fruit production and quality in grapefruit. Soil Science Society of America Journal 67, 583-588.

19. Jones, W.W., 1954. Biuret toxicity of urea foliage sprays on citrus. Science 120, 499-500.

20. Jones, W.W., Embleton, T.W., Goodall, G.E., 1955. Yellow tip of citrus application and biuret content of urea affect extent of leaf tip chlorosis. California Agriculture 9(12), 4.

21. Kato, T., Kubota, S., Bambang, S., 1982. Uptake of ¹⁵N-nitrate by citrus trees in winter and repartitioning in spring. Journal of the Japanese Society of Horticultural Science 50, 421-426.

22. Kusakabe, A., White, S.A., Walworth, J.L., Wright, G.C., Thompson, T.L., 2006. Response of microsprinkler-irrigated navel oranges to fertigated nitrogen rate and frequency. Soil Science Society of America Journal 70, 1623-1628.

23. Labanauskas, C.K., Handy, M.F., 1972. Nutrient removal by Valencia orange fruit from citrus orchards in California. California Agriculture 26(12), 3-4.

24. Legaz, F., Primo-Millo, E., Primo-Yufera, E.X., Gil, C., 1981. Dynamics of ¹⁵N labeled nitrogen nutrients in Valencia orange trees. International Society of Citriculture 2, 575-582.

25. Lovatt, C.J., 1999. Timing citrus and avocado foliar nutrient applications to increase fruit set and size. HortTechnology 9, 607-612.

26. Lovatt, C.J., 2013. Properly timing foliar-applied fertilizers increases efficacy: A review and update on timing foliar nutrient applications to citrus and avocado. HortTechnology 23, 536-541.

27. Lovatt, C.J., 2014. Nutrient deficiency and correction. In: Ferguson, L., Grafton-Cardwell, E.E. (Eds.). Citrus Production Manual. pp. 161-182.

28. Martinez-Alcantara, B., Quinones, A., Forner-Giner, M. A., Iglesias, D.J., Primo-Millo, E,, Legaz, F., 2012. Impact of fertilizer-water management on nitrogen use efficiency and potential nitrate leaching in citrus trees. Soil Science and Plant Nutrition 58, 659-669.

29. Menino, M.R., Carranca, C., de Varennes, A., 2007. Distribution and remobilization of nitrogen in young non-bearing orange trees grown under Mediterranean conditions, Journal of Plant Nutrition, 30, 1083-1096.

30. Mikkelsen, R.L., 2007. Biuret in urea fertilizers. Better Crops 91(3), 6-7.

31. Morgan, K.T., Scholberg, J.M.S., Obreza, T.A., Wheaton, T.A., 2006. Size, biomass, and nitrogen relationships with sweet orange tree growth. Journal of the American Society of Horticultural Science 131, 149-156.

32. Morgan, K.T., Obreza, T.A., Scholberg, J.M.S., 2007. Orange tree fibrous root length distribution in space and time. Journal of the American Society of Horticultural Science 132, 262-269.

33. Morgan, K.T., Wheaton, T.A., Castle, W.S., Parson, L.R., 2009. Response of young and maturing citrus trees grown on a sandy soil to irrigation scheduling, nitrogen fertilizer rate, and nitrogen application method. HortScience 44, 145-150.

34. Morgan, K., Scholberg, J., Obreza, T., Wheaton, T., 2012. Seasonal nitrogen budgets of mature citrus trees on a sandy entisol. Journal of Plant Nutrition 35, 2009-2023.

35. Niederholzer, F., 2011. a href="http://thealmonddoctor.com/general/using-urea-efficiently/" >Using urea efficiently.

36. Niederholzer, F., 2012. a href="http://cesutter.ucanr.edu/news_204522/Pomology_Notes/?newsitem=42838" >Nitrogen use efficiency in almonds. Sacramento Valley Almond News, April 2012.

37. Obreza, T.A., Zekri, M., Futch, S.H., 2008. General soil fertility and citrus tree nutrition. In: Obreza, T.A., Morgan, K.T. (Eds.). Nutrition of Florida Citrus Trees. 2nd Edition. University of Florida IFAS Extension. pp. 16-23.

38. Obreza, T.A., Morgan, K.T., Albrigo, L.G., Boman, B.J., 2008. Recommended fertilizer rates and timing. In: Obreza, T.A., Morgan, K.T. (Eds.). Nutrition of Florida Citrus Trees. 2nd Edition. University of Florida IFAS Extension. pp. 48-59.

39. Paramasivam, S., Alva, A.K., Fares, A., Sajwan, K.S., 2001. Estimation of nitrate leaching in an Entisol under optimum citrus production. Soil Science Society of America Journal 65, 914-921.

40. Quinones, A., Martinez-Alcantara, B., Legaz, F., 2007. Influence of irrigation system and fertilization management on seasonal distribution of N in the soil profile and on N-uptake by citrus trees. Agriculture, Ecosystems and Environment 122, 399-409.

41. Rabe, E., 1994. Yield benefits associated with pre-blossom low-biuret urea sprays on Citrus spp. Journal of Horticultural Science 69, 495-500.

42. Schwankl, L.J., 2014. Fertigation. In: Ferguson, L., Grafton-Cardwell, E.E. (Eds.). Citrus Production Manual. pp. 197-204.

43. Weinert, T.L., Thompson, T.L., White, S.A., Maurer, M.A., 2002. Nitrogen fertigation of young navel oranges: Growth, N status, and uptake of fertilizer N. HortScience 37, 334-337.

44. Zasoski, R.J., 1994. Nitrogen efficiency in drip irrigated almonds. FREP Final Report.

45. Zheng, Y., Khuong, T., Lovatt, C.J., Faber, B.A., 2013. Comparison of different foliar fertilization strategies on yield, fruit size and quality of 'Nules' Clementine mandarin. Acta Horticulturae 984, 247-255.

Phosphorus

1. Albrigo, L.G., 1999. Effects of foliar applications of urea or Nutri-Phite on flowering and yields of Valencia orange trees. Proceedings of the Florida State Horticultural Society 112, 1-4.

2. Bingham, F.T., Martin, J.P., 1955. Minor nutrients of citrus. California Agriculture 9(9), 4-5.

3. Chapman, H.D., 1960. Leaf and soil analyses as guide for citrus fertilizer practices in southern California orchards. California Agriculture 14(10), 13-14.

4. Chapman, H.D., 1968. The mineral nutrition of citrus. In: Reuther, W., Batchelor, L.D., Webber, H.J. (Eds.). The Citrus Industry, Volume II. University of California, Division of Agricultural Sciences. pp. 127-289.

5. Chapman, H.D., Fullmer, F., 1951. Leaf analysis of citrus. California Agriculture 5(9), 6.

6. Crowley, D., 2012. Macronutrients: Their role in citrus production. Presentation held at the California Citrus Conference, Porterville, October 10-11, 2012.

7. Embleton, T.W., Jones, W.W., 1974. Foliar-applied nitrogen for citrus fertilization. Journal of Environmental Quality 3, 388-391.

8. Embleton, T.W., Jones, W.W., Platt, R.G., Burns, R.M., 1974. Potassium nutrition and deficiency in citrus. California Agriculture 28(8), 6-8.

9. Embleton, T.W., Jones, W.W., Platt, R.G., 1976. Leaf analysis as a guide to citrus fertilization. In: Reisenauer, H.M. (Ed.). Soil and Plant-Tissue Testing in California. University of California Cooperative Extension Bulletin 1879. pp. 4-9.

10. Faber, B., 2013. Citrus and avocado leaf analysis. Topics in subtropics. ANR blogs.

11. Fulton, A., 2010. Understanding and applying information from a soil test: Part 2 - NPK.

12. Haas, A.R.C., 1936. Phosphorus deficiency in citrus. Soil Science 42(2), 93-105.

13. Labanauskas, C.K., Handy, M.F., 1972. Nutrient removal by Valencia orange fruit from citrus orchards in California. California Agriculture 26(12), 3-4.

14. Lovatt, C.J., 1999. Timing citrus and avocado foliar nutrient applications to increase fruit set and size. HortTechnology 9, 607-612.

15. Lovatt, C.J., 2014. Nutrient deficiency and correction. In: Ferguson, L., Grafton-Cardwell, E.E. (Eds.). Citrus Production Manual. pp. 161-182.

16. Morgan, K.T., Obreza, T.A., Scholberg, J.M.S., 2007. Orange tree fibrous root length distribution in space and time. Journal of the American Society of Horticultural Science 132, 262-269.

17. Noling, J.W., 2011. Citrus root growth and soil pest management practices. University of Florida IFAS Extension.

18. Obreza, T.A., Zekri, M., Futch, S.H., 2008. General soil fertility and citrus tree nutrition. In: Obreza, T.A., Morgan, K.T. (Eds.). Nutrition of Florida Citrus Trees. 2nd Edition. University of Florida IFAS Extension. pp. 16-23.

19. Obreza, T.A., Zekri, M., Hanlon, E.A., 2008. Soil and leaf tissue testing. In: Obreza, T.A., Morgan, K.T. (Eds.). Nutrition of Florida Citrus Trees. 2nd Edition. University of Florida IFAS Extension. pp. 24-32.

20. Obreza, T.A., Morgan, K.T., Albrigo, L.G., Boman, B.J., 2008. Recommended fertilizer rates and timing. In: Obreza, T.A., Morgan, K.T. (Eds.). Nutrition of Florida Citrus Trees. 2nd Edition. University of Florida IFAS Extension. pp. 48-59.

21. Sanden, B., Fullton, A., Ferguson, L., 2014. Soil and water analysis and amendment. In: Ferguson, L., Grafton-Cardwell, E.E. (Eds.). Citrus Production Manual. pp. 131-146.

22. Schwankl, L.J., 2014. Fertigation. In: Ferguson, L., Grafton-Cardwell, E.E. (Eds.). Citrus Production Manual. pp. 197-204.

23. Zekri, M., Obreza, T., 2013. Phosphorus (P) for citrus trees. University of Florida IFAS Extension.

Potassium

1. Albrigo, L.G., 1999. Effects of foliar applications of urea or Nutri-Phite on flowering and yields of Valencia orange trees. Proceedings of the Florida State Horticultural Society 112, 1-4.

2. Boman, B., Obreza, T., 2012. Fertigation nutrient sources and application considerations for citrus. University of Florida IFAS Extension.

3. Calvert, D.V., Smith, R.C., 1972. Correction of potassium deficiency of citrus with KNO₃ sprays. Journal of Agricultural Food Chemistry 20, 659-661.

4. Chapman, H.D., 1960. Leaf and soil analyses as guide for citrus fertilizer practices in southern California orchards. California Agriculture 14(10), 13-14.

5. Chapman, H.D., 1968. The mineral nutrition of citrus. In: Reuther, W., Batchelor, L.D., Webber, H.J. (Eds.). The Citrus Industry, Volume II. University of California, Division of Agricultural Sciences. pp. 127-289.

6. Chapman, H.D., Fullmer, F., 1951. Leaf analysis of citrus. California Agriculture 5(9), 6.

7. Crowley, D., 2012. Macronutrients: Their role in citrus production. Presentation held at the California Citrus Conference, Porterville, October 10-11, 2012.

8. Embleton, T.W., Jones, W.W., 1974. Foliar-applied nitrogen for citrus fertilization. Journal of Environmental Quality 3, 388-391.

9. Embleton, T.W., Jones, W.W., Platt, R.G., Burns, R.M., 1974. Potassium nutrition and deficiency in citrus. California Agriculture 28(8), 6-8.

10. Embleton, T.W., Jones, W.W., Platt, R.G., 1976. Leaf analysis as a guide to citrus fertilization. In: Reisenauer, H.M. (Ed.). Soil and Plant-Tissue Testing in California. University of California Cooperative Extension Bulletin 1879. pp. 4-9.

11. Faber, B., 2013. Citrus and avocado leaf analysis. Topics in subtropics. ANR blogs.

12. Fulton, A., 2010. Understanding and applying information from a soil test: Part 2 - NPK.

13. Labanauskas, C.K., Handy, M.F., 1972. Nutrient removal by Valencia orange fruit from citrus orchards in California. California Agriculture 26(12), 3-4.

14. Lovatt, C.J., 1999. Timing citrus and avocado foliar nutrient applications to increase fruit set and size. HortTechnology 9, 607-612.

15. Lovatt, C.J., 2014. Nutrient deficiency and correction. In: Ferguson, L., Grafton-Cardwell, E.E. (Eds.). Citrus Production Manual. pp. 161-182.

16. Morgan, K.T., Obreza, T.A., Scholberg, J.M.S., 2007. Orange tree fibrous root length distribution in space and time. Journal of the American Society of Horticultural Science 132, 262-269.

17. Noling, J.W., 2011. Citrus root growth and soil pest management practices. University of Florida IFAS Extension.

18. Obreza, T.A., Zekri, M., Futch, S.H., 2008. General soil fertility and citrus tree nutrition. In: Obreza, T.A., Morgan, K.T. (Eds.). Nutrition of Florida Citrus Trees. 2nd Edition. University of Florida IFAS Extension. pp. 16-23.

19. Obreza, T.A., Morgan, K.T., Albrigo, L.G., Boman, B.J., 2008. Recommended fertilizer rates and timing. In: Obreza, T.A., Morgan, K.T. (Eds.). Nutrition of Florida Citrus Trees. 2nd Edition. University of Florida IFAS Extension. pp. 48-59.

20. Parker, E.R., Jones, W.W., 1950. Fruit size and leaf composition concentration of potassium in orange leaves found to be associated with fruit size. California Agriculture 4(5), 4.

21. Sanden, B., Fullton, A., Ferguson, L., 2014. Soil and water analysis and amendment. In: Ferguson, L., Grafton-Cardwell, E.E. (Eds.). Citrus Production Manual. pp. 131-146.

22. Schwankl, L.J., 2014. Fertigation. In: Ferguson, L., Grafton-Cardwell, E.E. (Eds.). Citrus Production Manual. pp. 197-204.

23. Spiegel-Roy, P., Goldschmidt, E.E., 1996. The Biology of Citrus. Cambridge University Press. Cambridge, UK.

24. Zekri, M., Obreza, T., 2013. Potassium (K) for citrus trees. University of Florida IFAS Extension.

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CDFA - FREP - CA Fertilization Guidelines - Citrus

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The fertilization guidelines on this site have been redesigned to be compliant with AB434. The guidelines in the traditional design with the latest updates can be found on the UC Davis Nutrient Management website . Albrigo, L.G., 1999. Effects of foliar applications of urea or Nutri-Phite on flowering and yields of Valencia orange trees.

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The First & Zeroth Laws of Thermodynamics: Crash Course Engineering #9

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As I planned for my mole unit this year, I thought about how fundamental the mole concept is for stoichiometry and brainstormed ways to really make it stick. I usually do a lab practicum at the end of every unit. I have shared about my Lab Practicums in Chemistry before. For the mole unit, I decided to do multiple mini-practicums, one for each learning target of the unit. Here are my learning targets and a brief description of the mini-practicums I did.

Target 1: I can convert between mass and moles of an element or compound.

For this learning target, I gave students the "mole mug brownie" recipe and conversion chart (figure 1) and asked them to convert the measurements to the dreaded imperial units we use to bake with.
Figure 1: Recipe and Data for Converting Units
After students did all of their math, they did get to test out their calculations by actually making the mole mug brownie. Reviews on the actual brownie were mixed but the math concepts definitely stuck!

Target 2: I can convert between the number of particles and moles of an element or compound.
Figure 2: Directions for Chalk Challenge
For this learning target, I gave each group a stick of chalk and the challenge in figure 2.
Figure 3: Chalk Signature on Lab Counter
While this practicum did not have an edible element, students really enjoyed writing on their lab stations (see figure 3) with chalk!

Target 3: I can relate the molar concentration (molarity) of a solution to the number of moles and volume of the solution.

For this learning target, I tried something I had never done before. I gave each group a small (50 - 100mL) volumetric flask and a given molarity (different molarity for each group). It was up to each group to mix a solution of copper (II) chloride to their given molarity. I tested each group's solution using my Vernier SpectroVis and a Beer's Law curve I had created the day before. Students thought the spectrometer was pretty cool and enjoyed the instant confirmation that they mixed their solution correctly.

Target 4: I can determine the empirical formula of a compound given the mass or percent composition.

For this learning target, I used my typical end of the unit practicum, find the formula of a hydrate. I have used different hydrates in the past but this year I used copper (II) sulfate pentahydrate. If you have not done this lab before, it is super simple and yields reliable data. Students heat their hydrate in a crucible to drive off all of the water. They use the before and after masses to calculate their moles of water in their sample and ratio it to their moles of copper (II) sulfate. The only thing I provide my students before they begin is a brief introduction to hydrates and an overview of how to heat a sample using a crucible.

I also have a learning target for molecular formulas (I can determine the molecular formula of a compound given the mass or percent composition and molar mass) but I did not make a separate practicum for it. Instead, I gave students the accepted molar mass for the copper (II) sulfate pentahydrate they were testing to compare their lab data to.

Since the mole unit involves a lot of practice, these practicums were a nice way to break up the worksheet/whiteboarding cycle, keep students engaged and reinforce concepts!

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We all know how fundamental the mole concept is for stoichiometry. This year I brainstormed ways to really make it stick. I decided to do multiple mini-practicums, one for each learning target of the mole unit. I am sharing brief descriptions of the mini-practicums I did for each learning target.

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Patterns Chemistry is an instructional resource for a year-long high school introductory chemistry course. It meets many of the physical science standards from the Next Generation Science Standards, as well as some earth science standards.

Through scientific inquiry, engineering design, and critical thinking, students discover and apply patterns in major Chemistry topics such as atomic structure, periodic trends, chemical reactions, and chemical bonding. Earth science topics relating to weather and climate in the context of chemistry are also explored. An important aim of the course is to challenge and further develop students' problem solving skills, scientific literacy and communication skills.

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Patterns Chemistry is an instructional resource for a year-long high school introductory chemistry course. It meets many of the physical science standards from the Next Generation Science Standards, as well as some earth science standards. Through scientific inquiry, engineering design, and critical thinking, students discover and apply patterns in major Chemistry topics such as atomic structure, periodic trends, chemical reactions, and chemical bonding.

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New Visions for Public Schools - Google Classroom ready resources

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Why do Pressure Cookers Cook Our Food Faster? (Phase Changes and Gas Pressure): Chem Remote Learning Plan

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Infographics on many topics

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Alcohol Chemistry(19) Analytical Chemistry(9) Aroma Chemistry(21) Atmospheric Chemistry(13) Biochemistry(70) Biology(13) Book(5) C&EN(84) Chemical Concerns(9) Chemical Reactions(6) Chemical Warfare(5) Chemistry Advent(5) Chemistry History(30) Chemistry in the News(44) ChemMonthly(3) Chemunicate(13) ChemVsCOVID(8) Christmas Chemistry(13) Cleaning Chemistry(2) Climate Crisis(1) Cocktail Chemistry(1) Colourful Chemistry(21) Coronavirus(17) Cosmetic Chemistry(11) Crime Scene Chemistry(2) Elements(8) Environmental Chemistry(7) Everyday Compounds(10) Food Chemistry(71) General Chemistry(28) Geochemistry(1)...

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Examine the effects of both the size and concentration of zinc oxide nanoparticles on the efficiency of sunscreen. View the penetration of ultraviolet light on the skin, and visualize the photon-nanoparticle interaction at the nanoscopic scale.

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Virtual Labs, autograded problems, resources by topic.

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ChemCollective Resources

The ChemCollective is a collection of virtual labs, scenario-based learning activities, tutorials, and concept tests. Teachers can use our content for pre-labs, for alternatives to textbook homework, and for in-class activities for individuals or teams. Students can review and learn chemistry concepts using our virtual labs, simulations, and tutorials. The ChemCollective is organized by a group of faculty and staff at Carnegie Mellon who are interested in using, assessing, and creating engaging online activities for chemistry education.

Chemistry resources for high schools impacted by COVID-19

The following free resources may be especially useful for online teaching of high school chemistry courses.

Open Learning Initative (OLI) General Chemistry I and II are complete online courseware for AP and college level chemistry. Each module includes short amounts of text, interactive worked examples, scaffolded practice problems, and assessments. The integration of these components provides a seamless and interactive learning experience for your students. The courseware also provides instructors with data on student performance, which they can use to adapt their instruction to student needs.

NGSS Chemistry Modules These online materials for a first course in chemistry aim to teach and reinforce chemistry concepts in the context of real-world scenarios, while incorporating virtual lab activities and strengthening student application of NGSS practices.

ChemCollective virtual labs The virtual labs hosted here allow students to design and carry out their own experiments. You can provide experimental procedures to your students or allow them to invent their own. The autograded labs create unknowns and provide feedback on students answers. Please contact for information on how to best use these with your students.

You can get immediate access to the open-and-free versions of General Chemistry I and General Chemistry II. To access the NGSS materials, please follow the instructions on chemvlab.orb. (At present, you need to sign up for an account and wait for approval, but we are working on ways to allow immediate access for evaluation. A single free account gets you free access to the NGSS materials along with General Chemistry I and II.)
A recording from our webinar on March 16 is available here. A discussion of the virtual lab starts at about 29:00. The earlier portions give an overview of the OLI General Chemistry I and II courseware. We also created an editable google doc to provide additional information on virtual labs, and help instructors collaborate on use of these labs.

Featured Resource

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The ChemCollective is a collection of virtual labs, scenario-based learning activities, tutorials, and concept tests. Teachers can use our content for pre-labs, for alternatives to textbook homework, and for in-class activities for individuals or teams. Students can review and learn chemistry concepts using our virtual labs, simulations, and tutorials.

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In this segment, the students learn about different models of the atom, including Dalton's model, Thomson's model, Rutherford's model, and the Bohr model.

In this segment, the students learn about different models of the atom, including Dalton's model, Thomson's model, Rutherford's model, and the Bohr model.
Premiere Date: July 10, 2016 | Runtime: 00:09:14

Toolkit

Unit 3A Note Taking Guide & Segment Questions
Download

Science & Engineering Practices

Analyzing and Interpreting Data

Once collected, data must be presented in a form that can reveal any patterns and relationships and that allows results to be communicated to others. Because raw data as such have little meaning, a major practice of scientists is to organize and interpret data through tabulating, graphing, or statistical analysis. Such analysis can bring out the meaning of data-and their relevance-so that they may be used as evidence.
Engineers, too, make decisions based on evidence that a given design will work; they rarely rely on trial and error. Engineers often analyze a design by creating a model or prototype and collecting extensive data on how it performs, including under extreme conditions. Analysis of this kind of data not only informs design decisions and enables the prediction or assessment of performance but also helps define or clarify problems, determine economic feasibility, evaluate alternatives, and investigate failures. (NRC Framework, 2012, p. 61-62)

Generating a Hypothesis and Developing a Model

Modeling can begin in the earliest grades, with students' models progressing from concrete "pictures" and/or physical scale models (e.g., a toy car) to more abstract representations of relevant relationships in later grades, such as a diagram representing forces on a particular object in a system. (NRC Framework, 2012, p. 58)

Vocabulary

Georgia Standards of Excellence

Develop and use models to compare and contrast the structure of atoms, ions and isotopes. SPS1.a
(Clarification statement: Properties include atomic number, atomic mass and the location and charge of subatomic particles.)

Analyze and interpret data to determine trends of the following: SPS1.b
* number of valence electrons
* types of ions formed by main group elements
* location and properties of metals, nonmetals, and metalloids
* phases at room temperature

Request Teacher Toolkit

The Chemistry Matters teacher toolkit provides instructions and answer keys for labs, experiments, and assignments for all 12 units of study. GPB offers the teacher toolkit at no cost to Georgia educators. Complete and submit this form to request the teacher toolkit. You only need to submit this form one time to get materials for all 12 units of study.

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Chemistry Matters | Unit 3 - Segment A | Georgia Public Broadcasting

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In this segment, the students learn about different models of the atom, including Dalton's model, Thomson's model, Rutherford's model, and the Bohr model. In this segment, the students learn about different models of the atom, including Dalton's model, Thomson's model, Rutherford's model, and the Bohr model.

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OER Chemistry 2 Structure of Matter Resource Guide

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When implementing NGSS standards, the science and engineering practice of argumentation can be seamlessly implemented through the use of formative assessment probes. Paige Keeley's NSTA press books are phenomenal resources of probes that can be used for a variety of topics. The probing statement/question provides a picture or scenario and potential answers. I facilitate a working group of chemistry teachers in the New York area and we recently created our own activity surrounding the topic of oxidation. The goal of the probe was to force students to think about what the meaning of oxidation is, as well as to allow students to engage in the science and engineering practice of argumentation. This was an introductory lesson to my oxidation and reduction unit prior to students learning the terms oxidation and reduction.

The following is the initial probe that was provided to students.

On the wall were the letters , and , each on a large piece of paper. Students were asked to read the probe and to place a yellow sticky note for the first choice, a blue sticky note for the second choice, and green sticky note on the wall to show their prediction. The wall provided a nice visual to me, as the teacher, of my students' preconceptions on the topic.

The students then met as a group in the designated areas with other classmates that shared the same first choice of Post-It color, meaning the same idea of what the term oxidation means. I assigned all the students who chose choice "" to meet in one area of the room with a large white board. Those students in favor of choice "" met in the opposite corner with a white board, the ""s in another and a fourth group was created as an overflow group because by group "a" was initially most of the class. As a group, students came up with two points to support the groups' argument that rationalized their choice. A group member wrote down the groups' rationale on a large whiteboard and a spokesperson reported out.

Next aluminum foil was added to an aqueous solution of copper(II) chloride. Students were asked to write down their observations to the demonstration. They then were given the following probe and asked to describe their thinking and provide an explanation for their answer.

Students again met in the designated areas of the room with a group that best fit their choice. Students provided additional information to support their argument on the original whiteboard at their locations. Students who no longer agreed with the original argument were free to move to another group that better fit their view. A spokesperson reported out for each group.

A final probe was provided to students:

Students were again asked to describe their thinking and provide an explanation for their response. Students again found a group that best fit their answer to the probe and added more points to support the groups' argument. Again, students who no longer agreed with the argument were free to move to another group that better fit their view. A spokesperson reported out key points for each group. Each student also recorded their own argument on their student handout.

Following the activity the students wrote a reflection on Microsoft Teams (you can use Google Classroom or paper version here as well) on how the process of argumentation allowed them to reason their final answer comparing the original Post-It choice to their final choice. Many students reflected on the need to develop a systematic approach to determine when oxidation was occuring. This provided a great introction to the need for oxidation numbers, a great segway into my next lesson. I found students less likely to complain about learning oxidation numbers than years past since they saw a need and purpose for them prior to learning about them in a lesson.
Remember to log into your ChemEd X account to access and download the Student Document.

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I facilitate a working group of chemistry teachers in the New York area and we recently created our own activity surrounding the topic of oxidation. The goal of the probe was to force students to think about what the meaning of oxidation is, as well as to allow students to engage in the science and engineering practice of argumentation.

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Understanding science at a glance: Several infographics about the topic "Agriculture" can be downloaded here, for adding substance to any presentation.

Use the New Zoom Function to Preview Infographics!

Move the mouse over the infographics or touch them on your mobile device to enlarge the graphics.

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research- The Bayer Scientific Magazine 2017 - Service

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Understanding science at a glance: Several infographics about the topic "Agriculture" can be downloaded here, for adding substance to any presentation. Move the mouse over the infographics or touch them on your mobile device to enlarge the graphics.

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Alcohol Chemistry(19) Analytical Chemistry(9) Aroma Chemistry(21) Atmospheric Chemistry(13) Biochemistry(70) Biology(13) Book(5) C&EN(84) Chemical Concerns(9) Chemical Reactions(6) Chemical Warfare(5) Chemistry Advent(5) Chemistry History(30) Chemistry in the News(44) ChemMonthly(3) Chemunicate(13) ChemVsCOVID(8) Christmas Chemistry(13) Cleaning Chemistry(2) Climate Crisis(1) Cocktail Chemistry(1) Colourful Chemistry(21) Coronavirus(17) Cosmetic Chemistry(11) Crime Scene Chemistry(2) Elements(8) Environmental Chemistry(7) Everyday Compounds(10) Food Chemistry(71) General Chemistry(28) Geochemistry(1)...

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Introduction

In this activity you will explore the structure and properties of atoms. You will construct models of atoms with properties of particular mass and charge; create models of atoms with different stabilities by adding or subtracting neutrons, protons, and electrons to a model atom; and determine that the same element may have varying number of neutrons and these form isotopes.
What is a recent model of an atom?
The atomic model previously taught was the Bohr Model. This model describes a nucleus made from positive protons and neutral neutrons, while negative electrons orbit the nucleus like planets orbit the sun.

Evidence indicated that electrons are in different energy levels, but no evidence can be found that verifies that the electrons are in the Bohr planetary orbits. This portion of the Bohr model is not supported by evidence.

Work started by Erwin Schrodinger in 1925 paved the way for our modern understanding of the atom. The nucleus is the same as in the Bohr model, but the electrons behave very differently. Instead of saying that electrons orbit at a particular distance from the nucleus, the best we can do is describe where you would likely find the electron if you were to look. The region of space where you are likely to find an electron around the nucleus is called an orbital. That region of likely electron location is indicated by the intensity of the blue color seen in the Orbital Model.

Use the draw tool to redraw and label the Orbital model of the atom above. Indicate where the protons, neutrons, and electrons are found, as well as what charge, if any, each of those particles has.

Standards

NSES Physical Science - Structures of Properties and Matter
The physical properties of compounds reflect the nature of the interactions among its molecules. These interactions are determined by the structure of the molecule, including the constituent atoms and the distances and angles between them.

Procedure

In the following model, you will be able to build an atom. By clicking on buttons, you will add (or remove) electrons, protons, and neutrons.

Collect Data I

The modern view of an atom consists of a nucleus made from protons and neutrons with electrons surrounding it in regions of high probability called orbitals. Different combinations of these three particles make up every kind of atom in the universe. There are about 100 known different elements - the substances listed on a periodic table.

Using the atom builder below, experiment with adding a proton, neutron and electron to make a different kind of atom. Click on the snapshot button and record your atom. Click OK to close the snapshot album.

Collect Data II

Now use the model to make a lithium atom in the fewest possible steps.

Click on the snapshot button and record your steps to solving this challenge. Click OK to close the snapshot album.

Collect Data III

Now use the model to make a carbon 12 atom in the fewest possible steps.

Click on the snapshot button and record your steps to solving this challenge. Click OK to close the snapshot album.

Analysis

Review your snapshot album, descriptions of images and previous responses to help answer the following questions.

Conclusion

Concluding Career STEM Question

Chemists work to study how different elements and compounds interact.

Further Investigation

Atoms are made from three different particles, and two of them are charged - the positive proton and the negative electron. These charges can reinforce and/or cancel each other. The net result is an atom that may or may not have an overall charge. If the atoms is charged, it is called an ion.

Try out the model. As you build atoms, pay close attention to how the number of electrons, protons, and neutrons affect the overall charge of the atom. Click on the snapshot button as you build several ions and record your steps to building them. Click OK to close the snapshot album.

Copyright © 2017 The Concord Consortium. All rights reserved. This activity is licensed under a Creative Commons Attribution 3.0 Unported License . The software is licensed under Simplified BSD , MIT or Apache 2.0 licenses. Please provide attribution to the Concord Consortium and the URL http://concord.org.

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Introduction In this activity you will explore the structure and properties of atoms. You will construct models of atoms with properties of particular mass and charge; create models of atoms with different stabilities by adding or subtracting neutrons, protons, and electrons to a model atom; and determine that the same element may have varying number of neutrons and these form isotopes.

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Your browser is looking a little out of date...

To get the best possible experience using our website, we recommend that you upgrade to latest version of this browser or install another web browser. See our Browser Support/Compatibility page for supported browsers list.

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ChemMatters Videos - American Chemical Society

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To get the best possible experience using our website, we recommend that you upgrade to latest version of this browser or install another web browser. See our Browser Support/Compatibility page for supported browsers list.

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A beautiful, free online scientific calculator with advanced features for evaluating percentages, fractions, exponential functions, logarithms, trigonometry, statistics, and more.

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Lots of options!

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Periodic Table Gallery - American Chemical Society

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American Chemical Society: Chemistry for Life.

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Introduction

In this activity you will explore the structure and properties of atoms. You will construct models of atoms with properties of particular mass and charge; create models of atoms with different stabilities by adding or subtracting neutrons, protons, and electrons to a model atom; and determine that the same element may have varying number of neutrons and these form isotopes.
What is a recent model of an atom?
The atomic model previously taught was the Bohr Model. This model describes a nucleus made from positive protons and neutral neutrons, while negative electrons orbit the nucleus like planets orbit the sun.

Evidence indicated that electrons are in different energy levels, but no evidence can be found that verifies that the electrons are in the Bohr planetary orbits. This portion of the Bohr model is not supported by evidence.

Work started by Erwin Schrodinger in 1925 paved the way for our modern understanding of the atom. The nucleus is the same as in the Bohr model, but the electrons behave very differently. Instead of saying that electrons orbit at a particular distance from the nucleus, the best we can do is describe where you would likely find the electron if you were to look. The region of space where you are likely to find an electron around the nucleus is called an orbital. That region of likely electron location is indicated by the intensity of the blue color seen in the Orbital Model.

Use the draw tool to redraw and label the Orbital model of the atom above. Indicate where the protons, neutrons, and electrons are found, as well as what charge, if any, each of those particles has.

Standards

NSES Physical Science - Structures of Properties and Matter
The physical properties of compounds reflect the nature of the interactions among its molecules. These interactions are determined by the structure of the molecule, including the constituent atoms and the distances and angles between them.

Procedure

In the following model, you will be able to build an atom. By clicking on buttons, you will add (or remove) electrons, protons, and neutrons.

Collect Data I

The modern view of an atom consists of a nucleus made from protons and neutrons with electrons surrounding it in regions of high probability called orbitals. Different combinations of these three particles make up every kind of atom in the universe. There are about 100 known different elements - the substances listed on a periodic table.

Using the atom builder below, experiment with adding a proton, neutron and electron to make a different kind of atom. Click on the snapshot button and record your atom. Click OK to close the snapshot album.

Collect Data II

Now use the model to make a lithium atom in the fewest possible steps.

Click on the snapshot button and record your steps to solving this challenge. Click OK to close the snapshot album.

Collect Data III

Now use the model to make a carbon 12 atom in the fewest possible steps.

Click on the snapshot button and record your steps to solving this challenge. Click OK to close the snapshot album.

Analysis

Review your snapshot album, descriptions of images and previous responses to help answer the following questions.

Conclusion

Concluding Career STEM Question

Chemists work to study how different elements and compounds interact.

Further Investigation

Atoms are made from three different particles, and two of them are charged - the positive proton and the negative electron. These charges can reinforce and/or cancel each other. The net result is an atom that may or may not have an overall charge. If the atoms is charged, it is called an ion.

Try out the model. As you build atoms, pay close attention to how the number of electrons, protons, and neutrons affect the overall charge of the atom. Click on the snapshot button as you build several ions and record your steps to building them. Click OK to close the snapshot album.

Copyright © 2017 The Concord Consortium. All rights reserved. This activity is licensed under a Creative Commons Attribution 3.0 Unported License . The software is licensed under Simplified BSD , MIT or Apache 2.0 licenses. Please provide attribution to the Concord Consortium and the URL http://concord.org.

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Introduction In this activity you will explore the structure and properties of atoms. You will construct models of atoms with properties of particular mass and charge; create models of atoms with different stabilities by adding or subtracting neutrons, protons, and electrons to a model atom; and determine that the same element may have varying number of neutrons and these form isotopes.

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Interactive periodic table showing names, electrons, and oxidation states. Visualize trends, 3D orbitals, isotopes, and mix compounds. Fully descriptive writeups.

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American Chemical Society Periodic Table including Electron Configuration and Ionization Energy.pdf

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ACS Middle School Session 4: Chemical Reactions – Ocean Acidification

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"The Chemical Bond Between Cloves and Nutmeg" focuses on the variety, strengths - and placement - of chemical bonds in the structures of two nearly identical molecules, eugenol and isoeugenol. In a "bonding" story of another kind, we profile Purdue materials chemist Jon Wilker, who's making synthetic adhesives based on the glues mussels produce underwater. (For another story on use of polymers in materials, see "The Science of Skis.") Also in this collection: early 19 th century illustrations of atom "combinations," and an 1888 recipe for household glue.

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"The Chemical Bond Between Cloves and Nutmeg" focuses on the variety, strengths - and placement - of chemical bonds in the structures of two nearly identical molecules, eugenol and isoeugenol. In a "bonding" story of another kind, we profile Purdue materials chemist Jon Wilker, who's making synthetic adhesives based on the glues mussels produce underwater.

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Periodic Table Gallery - American Chemical Society

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American Chemical Society: Chemistry for Life.

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My first year teaching chemistry, I was looking for a soap-making lab or activity that I could run in my chemistry class with 25-30 students working at the same time. I usually do this activity right before spring break, as it provides enough time for the soap to harden and cure (high school students are impatient to use their soaps right away, which you should not do with cold process soap). I have used the activity at different points in the curriculum: during intermolecular forces, during acids and bases, and during stoichiometry. Although I know teachers who use soap making as a project during their stoichiometry unit, I chose to not emphasize the calculations as it would require more time than I have available. Simply making the soap easily fits in a 45-minute period.

I found the basic recipe from the blog "Reflections of a Science Teacher" ¹, but I wanted to share how I have modified this procedure and other tips/tricks. I also provide students with background from a hot-process soap-making lab at Michigan State University ². I thought that hot-process soap, while taking less time for the soap to be ready to use, was too complex and had too many safety concerns for me to use in my own classroom. So far, I have tried this activity for three years with two different recipes.

In a basic soap recipe, oils reacts with the sodium hydroxide (lye) to produce soap and glycerin. Most cold process soap recipes include "superfatting", which simply means that the oil (the fat) is in excess to ensure that all of the sodium hydroxide is consumed. 3 Both of the soap recipes that follow have 5% superfatting with reduced water (33% instead of 38%) because the recipes mostly use liquid oils, and I used an online calculator ⁴ to check the amount of sodium hydroxide needed.
Figure 1 - Pulling soap out of cup/mold.
The first recipe uses only olive oil and canola oil; this is the cheapest and easiest method to use. The original blog post referenced, Reflections of a Science Teacher, used only olive oil; I chose to cut it with canola oil to reduce cost. A pure canola oil soap is also possible, but should be tested and the amount of lye required would need to be recalculated (there are plenty of lye calculators available online, such as SOAPCALC). The first recipe does not require the use of a hot plate to melt the oils. This soap takes a little longer to harden and should not be unmolded for at least two days.

Figure 2 - Soap using coconut and olive oil. Figure 3 - Soap using coconut and canola oil.

The second year I tried that we made soap in my course, I tried using olive oil, canola oil, and coconut oil. However, I found that the soaps were extremely soft. I wasn't expecting this, as coconut oil usually produces harder soaps (as it is a solid at room temperature). I have not been able to find an explanation for this but I suspect that more glycerin is being formed, leaving the soap softer. Since then, I modified the second recipe to include only olive oil and coconut oil OR canola oil and coconut oil, and found that this recipe produces a nice hard soap that can be easily unmolded after a day of curing. The canola/coconut soap was also a little wet immediately after unmolding (see figure 1), but after a day or two of curing in air looked fine. A hot plate is required to melt the coconut oil before it is mixed with the liquid oil.

In either case, the soap must be emulsified properly before it can be poured into the molds (plastic cups). I have used two methods that both work well - students can either stir and then the teacher can use a stick/immersion blender to complete the emulsification, or students can mix the soap in a mason jar. With a stick blender, it takes about 1-2 minutes to reach trace. ("Trace" refers to the point in soap making that the oils and lye solution have emulsified and begins to thicken. ⁵ In a tightly capped mason jar, 10-15 min of vigorous shaking will also completely emulsify the soap. I have usually done this lab before spring break, so the soaps will cure in the classroom for the week. Students can then unmold their soap when they return and wrap the soap in wax paper or place in a plastic bag to take it home. Technically, they should allow the soap to cure for at least another week before using the soap. This curing process allows excess water to evaporate and results in a harder soap. The pH of the soap will also continue to gradually decrease. The recommended curing time is 4-6 weeks for cold process soap. The longer the soap cures, the easier it will be to use, the longer the bar will last, and the gentler it will be on the skin. 3 However, the soap should be safe to use after 2-3 weeks of curing.

If you choose to use this lab, I would recommend looking at the resources on Soap Queen ³ (this is where I learned how to make soap at home). Note that "trace" for the soaps described here will be much less thick than the recipes on Soap Queen, particularly the version with only liquid oils. It really will look like vanilla cake batter. Also note that the students' bars will be about half the size shown in the photos, because I just poured the entire batch into one cup when I was testing the recipe this year to see which would be the best to use. This past year, I used the first recipe because of its simplicity, but the olive oil/coconut oil recipe will produce the nicest soap. I have taken home the bars that I have made for samples and any of them are fine soaps to use for hand washing (I wouldn't recommend them as a facial soap because they may be harsher than what we are used to). The longer the soaps sit before use, the harder they will be and the easier they will be to use.

An additional note: I have noticed that some students' soaps remain very soft and sticky after a week and are almost like Playdoh, regardless of the recipe used. While I am still not sure why this happens, I suspect it has to do with how the oils and lye are mixed together. The softer soaps will harden properly after several weeks and are still safe to use.

Safety notes: I pre-weighed the sodium hydroxide so that students did not have to worry about directly handling solid sodium hydroxide. I suggest you set out the pre-measured NaOH in beakers, plastic cups or weigh boats (do not use paper cups since NaOH is highly hydroscopic). I also had students wearing safety aprons, but a strong lecture on the importance of safety before they start was sufficient to make them be careful. Having some vinegar on hand is a good idea as well, to deal with any spills. If students spill raw soap on their skin, they should quickly rinse with plenty of water.

Also, the student resources include the following safety notes:

WEAR YOUR GOGGLES.

Be very careful with the sodium hydroxide. If you spill any NaOH on your skin, rinse with water IMMEDIATELY and call your instructor.

Be careful with the glass stir rod. If you are not gentle with it, it will break.

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My first year teaching chemistry, I was looking for a soap-making lab or activity that I could run in my chemistry class with 25-30 students working at the same time.

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Atomic theory is a common topic throughout any introductory chemistry course. Regardless of the depth given to the various models and the evidence that led to their creation, it's likely that Rutherford's gold foil experiment gets at least some attention in your course.

For me, this topic had always been a bit more lecture-based. Even though I thoroughly enjoyed talking about the history and development of the atom, I didn't like the feeling of being heavily reliant upon lecture. Additionally, I didn't like the fact that I wasn't providing students with an opportunity to generate their own evidence to support the concepts and models that I wanted them to develop. In this post, I propose a simple activity that gives students an opportunity to replicate Rutherford's experiment through an analogy experiment that may allow for easier conceptualization of the experiment itself and provide additional support for model development.

Before I mention anything to my students about Rutherford's experiment, I introduce them to an analogy experiment called Projectile Pennies. Though students don't yet know what exactly this is an analogy to, they will shortly. It is not imperative that they understand the analogy yet anyway. The goal of the experiment is presented to them as follows:

Indirectly calculate the diameter of an unknown object by recording the number of times it is hit with objects of a known diameter.

The key idea here is to emphasize the fact that they will be determining the diameter of something indirectly. All students understand what they would do if I asked them to determine the diameter of a circular object placed in front of them-simply measure it. But what if they were not able to see the object? Obviously this complicates things a bit. This provides a nice opportunity to discuss how often (especially in chemistry) we rely on indirect evidence to help us inferences about the primary claim that is being made.

The experimental setup (figure 1) and the materials needed are simple. Each group receives two meter sticks, 20 pennies, a whiteboard, and an object with a circular bottom. Typically, I give the groups full water bottles to ensure they have enough mass, but you can use different items with a variety of sizes (film canisters, water filled beakers...).
Figure 1: Side view of experimental setup (left). Top view of experimental setup (right).
One person in the group is designated as the "penny shooter." While the other members of the group are getting set up, the penny shooter is told to wait out in the hall to avoid knowing the location of the unknown object. Ideally, we want the penny shooter to be unaware of the location of the object to limit the possibility of intentionally shooting pennies directly at the object. In this past, I have tried to decrease this bias even more by blindfolding the penny shooters and allowing them to wear headphones with music playing on full volume. Needless to say, students fight over who gets to be the penny shooter.

The other member(s) of the group have a few simple tasks before and during the experiment.

Getting Set Up

As seen in figure 1 above, students will establish the path by laying down two parallel meter sticks between 70 - 90 cm apart. Place the whiteboard on top of the meter sticks so it is just barely above the ground and can easily lean against a wall, desk, or lab table. Though the figure above suggests leaning it against a wall, it is easier for the group if the whiteboard can lean against something that does not allow pennies to come back unless they hit the unknown object. Once the whiteboard is secure, place the object somewhere behind the whiteboard. Do not place the object directly next to the meter sticks. Before they tell the penny shooter to come in, ensure that a penny can slide under the whiteboard and that the object cannot be seen from the shooter's perspective.

During the Experiment

The penny shooter will essentially slide the penny toward the whiteboard (the penny should not leave the floor at any point). Once the penny shooter is ready to begin firing pennies, the other group members have a few simple tasks:

1. Record the number of times the object is hit.

2. Ensure a clear path for the pennies (i.e. if a penny hits and then comes back, remove it from the path).

3. Once a round is over, collect the pennies and hand them back to the penny shooter for the next round.

Figure 2: Experimental Setup-Photo taken in my classroom
Typically, I tell each group that they need to fire at least 100 pennies (5 rounds of 20). If we have enough time, I may ask for more but 100 is usually sufficient. Once they have reached the appropriate amount of pennies fired, they record their data and any measurements made in the following table:

Table 1: Organizing data from the experiment

Once they have all the necessary data, I provide them with the equation below, which will allow them to calculate the experimental diameter of their unknown object.
Figure 3: Equation used to calculate experimental diameter of unknown object
Personally, I decide to give them the equation above simply to save time. However, I can imagine some teachers possibly adding a layer of depth to the investigation by having students derive the equation themselves. Once students have calculated the experimental diameter of the unknown object, they are asked to compare it to the known diameter. Though results will vary, several groups often get within 1 - 1.5 cm of the known diameter-pretty cool! From this experience, students gain insight as to how it is possible to determine the size of an object that cannot be seen.
Figure 4: Example data and calculation of diameter
Lastly, I provide four extension questions for each group to answer. Each question is meant to get students thinking about some of the inferences that will soon be made once we start talking about Rutherford's experiment.

1. If you were the one firing the pennies while doing the same experiment and you noticed that some of your pennies actually bounced back toward you, how would you interpret this observation?

2. What would this suggest about the mass of the unknown object relative to the penny?

3. If you knew that your penny had a positive charge and you witnessed the same effect, what could you conclude about the charge of the unknown object?

4. Why did the majority of your pennies not hit the unknown object?

Once we eventually get to discussing Rutherford's experiment, it is fun to see students make the connections between his experiment and our analogy. I will often hear things like, "Oh, so the alpha particles were just like our pennies!" and other statements describing the similarities between the nucleus and unknown object. Even the realization as to why the majority of pennies did not make contact with the unknown object being similar to the majority of alpha particles going straight through the gold foil is a cool one to hear. I believe having this experience prior to discussing Rutherford's experiment provides a strong foundation for our students to more easily connect the rather conceptual findings from Rutherford's experiment. I feel it is better than simply discussing the details of Rutherford's experiment head on and assuming everyone will just "get it." When teaching such abstract concepts in chemistry, the more connections we can allow our students to make with previous experience, the easier they will be able to assimilate such experiences with the appropriate concept.

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Atomic theory is a common topic throughout any introductory chemistry course. It is likely that Rutherford's gold foil experiment gets at least some attention in your course. I have used a simple activity that gives students an opportunity to replicate Rutherford's experiment through an analogy experiment that may allow for easier conceptualization of the experiment itself and provide additional support for model development.

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Conducting experiments with liquid nitrogen experiments is a sure-fire way to energize many chemistry lessons. Unfortunately, getting access to liquid nitrogen can be a bit difficult. I happen to purchase liquid nitrogen from Airgas; you might be able to find a branch near you here.

In the video below, you can see a particular experiment I perform for my students when discussing the gas laws. I like to call this experiment "The Misbehaving Balloon".

How do you think this experiment works? Also, do you have any experiments you enjoy doing with liquid nitrogen? Let me know your thoughts!

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Chemical Mystery #4: The Case of the Misbehaving Balloon

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Conducting experiments with liquid nitrogen experiments is a sure-fire way to energize many chemistry lessons. Unfortunately, getting access to liquid nitrogen can be a bit difficult. I happen to purchase liquid nitrogen from Airgas; you might be able to find a branch near you here.

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9 Awesome Science Tricks Using Static Electricity!

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Periodical | Ionic & Covalent Bonding | AACT

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AACT is a professional community by and for K-12 teachers of chemistry

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Atomic Electron Configurations

The electron configuration is a listing of which atomic orbitals are occupied by electrons, and how many electrons are in each type of atomic orbital. The "ground state" electron configuration is the lowest energy combination of electrons in the atomic orbitals. Your task is to discover what the ground state electron configurations are - and how these can be predicted from the periodic table.

The Energy Ladder is a graphical representation of an atom's electron configuration in which the orbitals are arranged vertically in the order of their relative energy levels. Each box on the energy ladder represents an atomic orbital that can contain 0, 1, or 2 electrons.

Upon completion of this interactive learning object, students will be able to:

Arrange the electrons in an atom to obtain the correct electron configuration

Connect the correct electron configuration with the lowest energy for the atom

Predict the correct electron configuration from the atom's position on the periodic table

If you are using this learning object as part of a class your teacher may ask you to complete the companion Worksheet.

Teachers: Please review the Instructor's Guide for tips on implementing this simulation in the classroom.

Atomic Electron Configurations

Easier

Harder

Higher Energy

Lower Energy

Shortcut Buttons

Information

Jodye Selco is a Professor of Science Education (in the Center for Excellence in Mathematics and Science Teaching - CEMaST) and Chemistry at California State Polytechnic University Pomona. She is actively involved in research in physical chemistry as well as the teaching and learning of chemistry by all students. Professor Selco has been working with the teachers in Rialto USD for many years and has developed many learning experiences in science for teachers and students in the Rialto USD which have been adopted by many other teachers.

April Dawn is the Lead, Senior Instructional Designer for eLearning at California State Polytechnic University, Pomona. She provides instructional design consultation to assist faculty in redesigning existing courses and developing new courses for online, hybrid and face-to-face modes of instruction.

Richard Feldman is a multimedia developer for eLearning at California State Polytechnic University, Pomona. He creates interactive simulations that help faculty demonstrate concepts that are otherwise difficult to explain to students.

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The electron configuration is a listing of which atomic orbitals are occupied by electrons, and how many electrons are in each type of atomic orbital. The “ground state” electron configuration is the lowest energy combination of electrons in the atomic orbitals. Your task is to discover what the gro…

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Electron Configuration Simulation

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ExploreLearning : Get hands-on, minds-on in math and science

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Electron Configuration Gizmo : ExploreLearning

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Create the electron configuration of any element by filling electron orbitals. Determine the relationship between electron configuration and atomic radius. Discover trends in atomic radii across periods and down families/groups of the periodic table.

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Interactives . The Periodic Table . What's In the Box

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Teacher resources and professional development across the curriculum

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ACS-Hach High School Chemistry Grant - American Chemical Society

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American Chemical Society: Chemistry for Life.

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Why Do Some Things Get Colder (or Hotter) When They React?

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In this high school physical sciences unit, students investigate why some substances absorb heat when they react, while others release it. Students first solve the mystery of where the energy goes in endothermic reactions by examining salt dissolution and using magnets as models for bonds.

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How often do you study elements in chemistry class? Only periodically?

Want to learn more about this centerpiece of chemistry? Take your pick from this collection of links about elements and the periodic table! Build an element ball, solve periodic puzzles, and check out some of the most unusual periodic tables you've ever seen.

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Periodic Table | ACS ChemClubs - American Chemical Society

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How often do you study elements in chemistry class? Only periodically? Want to learn more about this centerpiece of chemistry? Take your pick from this collection of links about elements and the periodic table! Build an element ball, solve periodic puzzles, and check out some of the most unusual periodic tables you've ever seen.

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The Innovative Technology in Science Inquiry project engages students in STEM activities through the integrated use of technologies that include modeling, computational thinking, and real-time data acquisition. This comprehensive project will assist teachers in preparing diverse students for STEM careers by engaging them in exciting, inquiry-based science projects.

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Why do clothes stick together in the dryer?

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Why do clothes stick together in the dryer?

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Colorful Convection Currents - Sick Science! #075

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Daly's Model of Subduction | HHMI BioInteractive

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You are accessing a resource from the BioInteractive Archive. Archived resources are not updated to reflect current scientific knowledge, technology, and/or pedagogy.

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Holmes' Model of Convection | HHMI BioInteractive

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An early continental drift model proposed that mantle convection can produce continental movement and new plate formation.

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Plate tectonics is the unifying theory of Earth science and explains many of the major features of how our planet operates. It accounts for Earth's history including the distribution of life and past climate change.

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Classroom Activities: What is My Carbon Footprint?

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Current consumption of fossil fuel releases more than 25 billion tons of CO 2 into the atmosphere every year. If current trends continue, there will be a tripling of atmospheric CO 2 by the end of the century-levels not seen for more than 40 million years.

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Exploratorium: the museum of science, art and human perception

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Put the can on its side on a table or the floor -- anyplace that's flat and smooth. Hold it with your finger until it stays still.

Rub the balloon back and forth on your hair really fast.

Hold the balloon about an inch in front of the can. The can will start to roll, even though you're not touching it!

Move the balloon away from the can -- slowly -- and the can will follow the balloon.

If you move the balloon to the other side of the can, the can will roll in the other direction.

How fast will the can roll? How far can you roll it before the can stops? Will it roll uphill?

If you have some friends with cans and balloons, you can have a race across the room or down the sidewalk.

Why does the soda can roll?

With Remote Control Roller, basically, you pile up electrons on one thing and use them to attract the protons in something else. When you rub a balloon on your hair, it ends up loaded with electrons. Those electrons can attract the protons in a soda can, the protons in a trickle of water, the protons in your hair, or the protons in a wall.
Why do clothes stick together in the dryer?
The attraction between protons and electrons can also make clothes stick together in the dryer.

When you dry clothes in the dryer, different fabrics rub together, and electrons from a cotton sock (for instance) may rub off onto a polyester shirt. That's why clothes sometimes stick together and make sparks when you pull them apart. You may have used antistatic sheets in your dryer. As these sheets bounce around with your clothes, they add a uniform antistatic coating to the fabric. Rather than cotton rubbing against polyester, you've got the antistatic coating on the cotton rubbing against the antistatic coating on the polyester. No electrons rub off-and you don't get any static cling.

A Xerox machine uses static electricity to make copies. When you rub a balloon on your head, the balloon is charged with electricity. Inside a Xerox machine is a plastic drum that is also charged. When you put a piece of paper on the glass, a copy of it goes onto the drum. Where there were dark places on the paper, the static charge on the drum attracts the black plastic toner powder. Then the powdered places go onto a blank piece of paper, and the paper is heated. The toner melts and makes black letters on the new piece of paper.

This and dozens of other cool activities are included in the Exploratorium's Science Explorer books, available for purchase from our

online store.

Published by Owl Books,
Henry Holt & Company, New York,
1996 & 1997

ISBN 0-B050-4536 & ISBN 0-8050-4537-6,
$12.95 each

© 1998

Exploratorium

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Science Activity: Race Soda Cans w/ Static Electricity | Exploratorium

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Put the can on its side on a table or the floor -- anyplace that's flat and smooth. Hold it with your finger until it stays still. Rub the balloon back and forth on your hair really fast. Hold the balloon about an inch in front of the can.

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Engage (Phenomenon): Balloons can pull aluminum cans 

# data[].attributes.subject
Engage (Phenomenon): Balloons can pull aluminum cans 

# data[].attributes.attachment_link.provider_name
Exploratorium: the museum of science, art and human perception

# data[].attributes.attachment_link.readable_text
Put the can on its side on a table or the floor -- anyplace that's flat and smooth. Hold it with your finger until it stays still.

Rub the balloon back and forth on your hair really fast.

Hold the balloon about an inch in front of the can. The can will start to roll, even though you're not touching it!

Move the balloon away from the can -- slowly -- and the can will follow the balloon.

If you move the balloon to the other side of the can, the can will roll in the other direction.

How fast will the can roll? How far can you roll it before the can stops? Will it roll uphill?

If you have some friends with cans and balloons, you can have a race across the room or down the sidewalk.

Why does the soda can roll?

With Remote Control Roller, basically, you pile up electrons on one thing and use them to attract the protons in something else. When you rub a balloon on your hair, it ends up loaded with electrons. Those electrons can attract the protons in a soda can, the protons in a trickle of water, the protons in your hair, or the protons in a wall.
Why do clothes stick together in the dryer?
The attraction between protons and electrons can also make clothes stick together in the dryer.

When you dry clothes in the dryer, different fabrics rub together, and electrons from a cotton sock (for instance) may rub off onto a polyester shirt. That's why clothes sometimes stick together and make sparks when you pull them apart. You may have used antistatic sheets in your dryer. As these sheets bounce around with your clothes, they add a uniform antistatic coating to the fabric. Rather than cotton rubbing against polyester, you've got the antistatic coating on the cotton rubbing against the antistatic coating on the polyester. No electrons rub off-and you don't get any static cling.

A Xerox machine uses static electricity to make copies. When you rub a balloon on your head, the balloon is charged with electricity. Inside a Xerox machine is a plastic drum that is also charged. When you put a piece of paper on the glass, a copy of it goes onto the drum. Where there were dark places on the paper, the static charge on the drum attracts the black plastic toner powder. Then the powdered places go onto a blank piece of paper, and the paper is heated. The toner melts and makes black letters on the new piece of paper.

This and dozens of other cool activities are included in the Exploratorium's Science Explorer books, available for purchase from our

online store.

Published by Owl Books,
Henry Holt & Company, New York,
1996 & 1997

ISBN 0-B050-4536 & ISBN 0-8050-4537-6,
$12.95 each

© 1998

Exploratorium

# data[].attributes.attachment_link.title
Science Activity: Race Soda Cans w/ Static Electricity | Exploratorium

# data[].attributes.attachment_link.description
Put the can on its side on a table or the floor -- anyplace that's flat and smooth. Hold it with your finger until it stays still. Rub the balloon back and forth on your hair really fast. Hold the balloon about an inch in front of the can.

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Video transcripts: https://nerdfighteria.info/cat/144

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history biology literature learning education science humanities school "world history" ap tests smart fun chemistry psychology apush whap study "crash cours...

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At Crash Course, we believe that high-quality educational videos should be available to everyone for free! Subscribe for weekly videos from our current courses! The Crash Course team has produced more than 45 courses on a wide variety of subjects, including organic chemistry, literature, world history, biology, philosophy, theater, ecology, and many more!

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Why Do Some Things Get Colder (or Hotter) When They React?

# data[].attributes.attachment_link.description
In this high school physical sciences unit, students investigate why some substances absorb heat when they react, while others release it. Students first solve the mystery of where the energy goes in endothermic reactions by examining salt dissolution and using magnets as models for bonds.

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Get access to files anywhere through secure cloud storage and file backup for your photos, videos, files and more with Google Drive.

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Jon Bergmann: Just how small is an atom?

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Just how small are atoms? Really, really, really small. This fast-paced animation from TED-Ed uses metaphors (imagine a blueberry the size of a football stadium!) to give a visceral sense of just how small atoms are. Lesson by Jon Bergmann, animation by Cognitive Media.

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IS 6 Dynamics of Chemical Reactions and the Environment.pdf

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IS 4 Chemical Reactions (HS Chemistry - 3 Course Model) Framework.pdf

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IS 3 Atoms, Elements and Molecules (HS Chemistry 3 course model) Framework.pdf

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California Science Framework 2016 IS 1 Chemistry in the Earth System

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Phenomenon: Exploding Baked Potato (turn off sound)

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Phenomenon: Exploding Baked Potato (turn off sound)

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Pressure, temperature and volume

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Summary

In this activity, students will interact with a web-based tutorial that uses a drag and drop interface in order to learn how to convert between units of measurement using dimensional analysis. The tutorial allows students to learn at their own pace, and also provides feedback while they are solving problems.

Grade Level

High or middle school

Objectives

By the end of this activity, students should be able to

Convert between units of measurement using dimensional analysis

Understand the purpose of using dimensional analysis for converting between units of measurement

Chemistry Topics

This activity supports students' understanding of

Quantitative Chemistry

Dimensional Analysis

Time

Teacher Preparation: minimal

Lesson: 45 minutes

Materials

Computer (must run on Windows), compatible with Adobe Flash

Calculator

Writing utensil

Student Handout

Safety

No specific safety precautions need to be observed for this activity.

Teacher Notes

For students to achieve the most during the tutorial session, the following conditions should be present:

The class has already been introduced to the role of units and are familiar with basic metric and English units.

Advanced students will often want to work through the website on their own. For students less confident in their math abilities, group them in pairs to facilitate discussion.

Students should be required to write down solved problems and not just use the tutorial. The tutorial gives them feedback, but they must transfer the learning to pencil and paper. The attached worksheet prompts them to do this.

I advise giving students the worksheet for one level and having them turn it in before moving on to the next level. This allows the teacher to monitor their progress.

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Classroom Resources | Unit Conversion Online Tutorial | AACT

# data[].attributes.attachment_link.description
In this activity, students will interact with a web-based tutorial that uses a drag and drop interface in order to learn how to convert between units of measurement using dimensional analysis.

# data[].attributes.attachment_link.readable_text
Summary

In this activity, students will interact with a web-based tutorial that uses a drag and drop interface in order to learn how to convert between units of measurement using dimensional analysis. The tutorial allows students to learn at their own pace, and also provides feedback while they are solving problems.

Grade Level

High or middle school

Objectives

By the end of this activity, students should be able to

Convert between units of measurement using dimensional analysis

Understand the purpose of using dimensional analysis for converting between units of measurement

Chemistry Topics

This activity supports students' understanding of

Quantitative Chemistry

Dimensional Analysis

Time

Teacher Preparation: minimal

Lesson: 45 minutes

Materials

Computer (must run on Windows), compatible with Adobe Flash

Calculator

Writing utensil

Student Handout

Safety

No specific safety precautions need to be observed for this activity.

Teacher Notes

For students to achieve the most during the tutorial session, the following conditions should be present:

The class has already been introduced to the role of units and are familiar with basic metric and English units.

Advanced students will often want to work through the website on their own. For students less confident in their math abilities, group them in pairs to facilitate discussion.

Students should be required to write down solved problems and not just use the tutorial. The tutorial gives them feedback, but they must transfer the learning to pencil and paper. The attached worksheet prompts them to do this.

I advise giving students the worksheet for one level and having them turn it in before moving on to the next level. This allows the teacher to monitor their progress.

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Classroom Resources | Unit Conversion Online Tutorial | AACT

# data[].attributes.attachment_link.description
In this activity, students will interact with a web-based tutorial that uses a drag and drop interface in order to learn how to convert between units of measurement using dimensional analysis.

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Phenomenon Video Clips w/ Unit Driving Questions

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Phenomenon Video Clips w/ Unit Driving Questions

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This lesson--the third in a series of three lesson plans about the Periodic Table of Elements--explains why the elements exhibit periodicity, why the periodic table of elements is shaped the way it is, and how we are able to predict the characteristics of elements yet to be discovered or created. Students create electron configuration diagrams that describe the arrangement of electrons around the nucleus. This lesson is the third of three lessons and is intended as an enhancement activity following completion of the first two lessons. The first lesson, The Periodic Table of the Elements, explored the origin of the periodic table. The second lesson, The Strange World of the Electron , described the structure of the atom.

Discover that electron sublevel structure is responsible for the periodicity of elements

Understand that the periodic table arranges elements in groups based on the energy sublevel of an element's highest energy electron

1. Show students the Quantum Mechanics video and lead a class discussion of the contemporary atomic model. Ask students:

What is the basic structure of the atom? (a small nucleus surrounded by tiny orbiting electrons and much space)

What keeps electrons in orbit around the nucleus? (Electrons orbit in specific energy levels within the space surrounding the nucleus.)

What can we know about individual electrons, and what is it impossible to know? (The exact position and momentum of an electron cannot be determined, but the probability of it occupying a particular location can be determined using wave equations.)

2. Pass out copies of the Quantum Mechanical Atom (PDF) handout and the Periodic Table of the Elements chart (PDF) handout and make sure that all students have scrap paper and pencils. Work through the Quantum document slowly with the entire class. Before moving on to the "Electron Configuration" section of the document, check to make sure that students have a clear understanding of the two tables in the "Levels and Sublevels" section.

3. Demonstrate how to write the electron configuration for lithium, the example given in the "Electron Configuration" section. Write the electron configurations for at least two more elements, such as beryllium and boron, so that students can begin to see a pattern.

4. Individually or in pairs, have students work out the electron configurations for the rest of the elements in row 2 of the periodic table (ending with neon). Then have students work out the electron configuration for sodium, in row 3, before reconvening as a class to discuss any difficulties they might have had moving up to a higher energy level.

5. Read the "Repeating Electron Patterns" section of the document with the class and work out the electron configurations for a few sample elements with atomic numbers of 21 or higher.

6. Now read the "Abbreviated Configurations" section of the document. Explain to the class that there are different ways to write electron configurations. Chemists usually prefer to use the most abbreviated notation possible. The electron configuration for krypton, for example, is usually written as [Ar] 4s ² 3d ¹⁰ 4p ⁶. Write this configuration on the board.

7. Then write the following:

Explain that this is the unabbreviated quantum number string for krypton, in which each individual piece of notation -- the 3p ⁵, for example -- represents a single electron. It's obviously much more cumbersome than the abbreviated form, but this type of notation can help us make the connection between electron configuration and the shape of the periodic table.

8. Start by circling the s sublevel electrons in the string, one at a time. After circling each one, ask students to find on the Periodic Table of the Elements Chart (PDF) handout the element for which that electron was the last to be added. For example, when you circle 3s ², students should look for the element whose highest energy electron is in the 3s ² position. This is magnesium. When you circle 4s ¹, students should look for the element whose highest energy electron is in the 4s ¹ position: potassium. Continue through all of the s sublevel electrons in the above string.

9. Repeat this exercise for all of the p sublevel electrons in the string.

10. By this time, most students will have recognized that those elements whose highest energy electrons are in s sublevels occupy the first two columns of their chart, and those whose highest energy electrons are in p sublevels occupy the last six columns. Discuss with students why they think this is. Remind students that there are two more sublevels, d and f. They hold a maximum of 10 and 14 electrons respectively. Each of these sublevels should also have its own block. Ask students how many columns they think each of these blocks should have.

Ask students to find information on the physical properties of at least three elements on the periodic table, each from a different group, or column. Have students write a short paragraph about each element, explaining, in terms of electron configuration, why their chosen elements might have the properties they do.

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Repeating Patterns: The Shape of the Periodic Table

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This lesson--the third in a series of three lesson plans about the Periodic Table of Elements--explains why the elements exhibit periodicity, why the periodic table of elements is shaped the way it is, and how we are able to predict the characteristics of elements yet to be discovered or created.

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Engage: Alien Periodic Trend Sort (Small deck of cards)

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Engage: Alien Periodic Trend Sort (Small deck of cards)

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Sort cards first "What patterns do you see?"

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Modeling Periodic patterns
Dusty Carroll 2017-08-02 05:10:12
Analyzing chemical reactions to determine trends in ionization energy and electron affinity Some chemical reactions are versatile and can be used with various topics to provide a valid educational experience. Two such reaction types are those of metals with acids and of halogens with alkali metal halides (Figures 1 and 2, respectively, pp. 44-45). I have used each of these reaction types for various lab purposes, including modeling single replacement reactions, determining an activity series, and writing net ionic equations as a part of redox chemistry. Both reaction types provide reliable data and typically work as predicted, which adds to their versatility. This article describes how these reactions could fill a laboratory gap in the chemistry curriculum while engaging students in evidence-based reasoning and aligning with the Next Generation Science Standards (NGSS Lead States 2013; see box, p. 49). Background: New uses for old reactions A teacher can address many topics when the class studies the patterns of the periodic table. A few years ago, my class was grappling with the reactivity of elements as evidenced by reactions they had performed in the lab. Because the reactivities of metals and nonmetals are explained with opposite reasons, I referred back to the original atomic properties we studied when first determining periodic patterns, specifically ionization energy (the energy required to remove an electron from an atom) and electron affinity (the energy released or spent when an electron is added to an atom). I elicited the students' prior learning by asking them why metals generally have lower ionization energy and electron affinity than nonmetals. (Simple answer: Larger atom size and lower effective nuclear charge leads to less attraction for the outer electrons or for any additional electron). We then discussed which type of atoms-metals or nonmetals- would more likely attract electrons away from another atom. (Simple answer: Nonmetal atoms because they are smaller, so their positive nuclei can get close to those extra electrons, and because they have a generally high effective nuclear charge, so their attractive force on any set of electrons would be high.) This discussion led to the generalization that metal atoms generally will lose electrons in a chemical reaction, and nonmetal atoms will gain or share electrons in a chemical reaction. Later, I realized I might purposefully use the reactivity of metals and of nonmetals to more concretely teach those original patterns of atomic properties. The reactions of metals with acids, if limited to calcium, magnesium, aluminum, and zinc, with hydrochloric acid, nicely correlate with both the period and group patterns in ionization energy (higher acid reactivity and lower ionization energy moving down a group or left across a period). The halogen/halide reactions perfectly model the electron affinity group trend (decreasing down a group, because the more-reactive chlorine will always attract electrons to end up in its anion form, while the less-reactive iodine won't attract electrons and has low attraction for its extra electron when in anion form, thus always ending in its neutral molecule form). Because chlorine, bromine, and iodine are the only halogens commonly available in high school labs, this investigation is limited to those three halogens and their alkali metal salts. Net ionic equation, halogen/halide: X2 + 2Y- à 2X- + Y2. Notes: X and Y are any two different halogen atoms. The halides are colorless in both water and oil, but the molecular halogens have specific colors in both solvents. The halogens are more soluble and have more distinct colors in the organic solvent than in the water, so extraction from the aqueous solution into oil provides a colorful and interesting way to identify the presence of each halogen. In water: Cl2 is pale yellow; Br2 and I2 are both orange-ish brown. In oil: Cl2 is pale yellow; Br2 is orange; and I2 is purple. Note that the atomic properties cannot truly be measured by these chemical reactions. In chemical reactions, students are using the bulk form of the substances, and many other factors beside their atomic nature influence their behavior. I don't usually permit "bad chemistry" in my classroom, but I reasoned that if students are told that our reactions only model the trend and do not measure it, then the infraction is acceptable. I also have students figure out why it would be difficult for us to do an experiment to study the "real" version of the properties. This typically leads to a good discussion. Student background preparation for the lessons On the days before the lab, students are introduced to the attractive forces between the particles of a given atom. This can be done in various ways. I typically use a POGIL (Process Oriented Guided Inquiry Learning) activity called "Coulombic Attraction" (Trout 2012, p. 67-72) to guide students toward the following understandings: Attraction is a force between particles of opposite charge (in this context, a nucleus and an electron) Because the nucleus is always in the middle of an atom, we frame our discussion in the context of electrons being attracted toward the nucleus. An electron close to the nucleus is more attracted than an electron far from the nucleus. An electron is more attracted to a nucleus with higher charge than to one of lower charge. Multiple electrons of equal distance don't "split" the attraction of the nucleus (they all experience the full attraction for that distance). Armed with a basic understanding of the laws of attraction, students are ready for the first laboratory lesson. Lesson 1: Ionization energies of metals In this introductory lab, students both determine and explain patterns in ionization energy as analyzed through the reactions of metals with acids. (See "On the web" for the student handout, which includes safety precautions and interactive notes and questions for students to answer, and for teacher notes.) Students should work in pairs, or, if equipment is limited, in groups of three or four. Prelab questions and discussion Using the questions provided online for this activity, the teacher guides a discussion before the lab begins. The purpose is to get students thinking about how atoms can turn into ions and how ions can turn into atoms. My students seem most successful when I alternate between large-group discussion and independent work as the class works through the various parts of the activity. You may choose to discuss first and have students answer the questions as confirmation. Or have students answer the questions first and use that as a basis for the discussion. Either way, make these points clear before beginning the experiment: Changes don't happen in isolation. Another force (or atom) must be involved (e.g., an electron will not just "fall off" an atom). One species (atom or ion) can "take" another species's electron if the first species has a stronger attraction to it. (This language is typical of students first exploring these ideas. You can correct them. "Attract an electron away from" is more accurate than "take an electron.") Although Bohr models aren't the accepted modern model of the atom, they provide a good visual representation of both atom size and shielding as well as nuclear charge. This helps students more easily notice the reasons for the patterns shown in their data. Collecting data Students wearing protective gloves, apron, and safety goggles begin by placing a small sample of each of four different metals into test tubes and adding enough 1M hydrochloric acid to completely cover the sample. They then write their observations in lab notebooks, using descriptive words so they can later rank the metals by their reactivity. Students should pay attention to both the speed and intensity of reactions. The teacher circulates, asking: "Why do you think that one is so much slower than the last one?" or, "Do you see any evidence of a reaction occurring? How long do you think you should wait to be able to rank this against the others?" It is important to notice, and correct, if needed, what students are writing because their notes often aren't descriptive enough to interpret their evidence later. The final ranking for the metals should be, from least to most reactive: aluminum, zinc, magnesium, calcium. If comparing to standard oxidation potentials or the metal activity series, the order would be zinc, aluminum, magnesium, calcium. The order differs for this lab because aluminum forms an amphoteric oxide coating that protects it against acids. I don't address this discrepancy if the lab occurs early in the year to avoid overloading students with concepts. Either way the metals are ranked, the group and period trends are still evident. Postlab questions: Analyzing data With the initial postlab questions, students are asked to analyze their results with respect to ionization energy, considering whether reactivity would be directly or inversely related to ionization energy. Students should realize that an atom with a larger ionization energy would have a greater attraction for its own electrons. This means there's a lower likelihood of the acid's H+ ion having enough attractive force to attract the electron away from that metal atom, so the reaction would be slow or nonexistent. The H+ ion would more likely have enough attractive force to attract away an electron from a metal atom with lower ionization energy (lower attraction for its own electrons), thus leading to a faster or stronger reaction. Students should use their observations as evidence to conclude that the ranking for ionization energy will be opposite of the ranking for reactivity. FIGURE 4 Example of a portion of the pre-lab discussion for the electron affinity lab. Two possibilities (Refer to the labeled reference set of test tubes so students can see the colors of each molecule in the organic layer.) Teacher: If a reaction occurs between chloride ion and bromine molecule, what color will you see in the organic layer? Desired answer: Pale yellow because chlorine molecule has formed and bromine molecule has reacted. Teacher: If a reaction does not occur between chloride ion and bromine molecule, what color will you see in the organic layer? Desired answer: Orange because the bromine molecule is still present, and chloride didn't turn into a molecule. Next, ask questions that lead students through identifying elements in the same group and in the same period and then using the ionization energy rankings to generalize a group pattern and a period pattern. This should lead them to conclude that ionization energy decreases down a group (calcium had a stronger reaction than magnesium) and increases across a period (aluminum was less reactive than magnesium, and zinc was less reactive than calcium). Postlab questions: Interpreting data One idea I constantly discuss with students is the difference between a pattern or phenomenon and the reasons for the pattern or phenomenon. When analyzing the data in the first several questions, the goal was simply to determine the patterns on the periodic table. Interpreting the data goes farther and asks students to give an evidence-based explanation for why these patterns exist. Students are next prompted to draw and use Bohr models (Figure 3) to justify the patterns using atomic structure and Coulombic attraction. To conclude the activity, students are asked to use the observed patterns to predict how two other metals would react with acid. Lesson 2: Electron affinities of the halogens In this lab, students both determine and explain patterns in electron affinity as analyzed through the reactions of halogens with alkali metal halides. (See "On the web" for the student handout, which includes safety precautions and interactive notes and questions for students to answer and for teacher notes.) Students should work in pairs. As a class reference, I prepare a set of large test tubes with a layer of aqueous solution and a layer of organic solvent for each of the six individual reactants (Figure 2). This helps show students that the ions, even if some are dissolved in the organic layer, remain colorless, while the molecules turn the organic layer a particular vivid color. This set remains at the front of the room where students can use it to compare their samples as needed. Prelab questions and discussion The student handout for this lesson includes prelab interactive notes and questions. Students should understand the difference between molecules and ions, so the prelab section of the student handout begins with a question that helps students recognize how ions and molecules are represented using chemical formulas. Other prelab questions focus on interpreting chemical equations using electron affinity. I ask students to read and try to understand the first page of the student handout. During discussion, I show them the reference solutions to help them make sense of the new information. Next I ask them to answer the concept questions individually, and then we review them as a class. I also show a set of ionic equations on the board (Figure 4) and talk through examples before the lab so students understand the evidence they are gathering. Though my students had not yet studied chemical reactions when performing this lab, they easily understood the symbolism of the chemical equations after a brief explanation. Collecting data During the lab, students react each of the aqueous molecular halogens with each of the related aqueous alkali metal halides, then extract the remaining molecules into the oil. It is unnecessary to react each halogen with its own ion, so there will be only six combinations. The teacher should clearly communicate how the students should obtain their materials throughout the procedures. Students must wear safety goggles, aprons, and gloves. When only one fume hood is available, the molecular halogens must be dispensed in the hood and students should cap their test tubes with stoppers before moving away from the hood. If an organic solvent other than paraffin oil is used, this may also need to be dispensed under the hood. The dropper bottles of aqueous alkali metal halides may be distributed to each lab group at their lab table. Once chemicals are obtained, the teacher should circulate to ensure that students mix the tubes enough to get a deep color. Also, the teacher should question each group on their analysis of at least one of the tubes to ensure they will have success when analyzing the final results. Postlab questions: Analyzing data Students should get results showing "purple" four times and "orange" two times. This should lead to the conclusion that iodine, whenever present in any form, ended as a molecule (I2). Chlorine, whenever present, ended as an ion (Cl-). Bromine, in any form, ended as a molecule (Br2) when with chlorine and as an ion (Br-) when with iodine. The student handout directs students to create a data table in their lab notebooks to record all results. The last column of the data table has a heading of "Analysis/Meaning." In this column, students should write a chemical equation to match their results and then describe what happened in terms of electrons (example, Figure 5, p. 47). Students should conclude that from highest to lowest electron affinity, the correct order is: chlorine, bromine, iodine. Postlab questions: Interpreting data Students are, again, guided toward drawing Bohr diagrams (Figure 6) for each halogen and using those, along with Coulomb's law, to explain the patterns identified in the lab. Students then use these ideas to make a prediction by extending the pattern to a reaction involving fluorine. Assessment I designed this lab series to introduce atomic properties and their periodic table trends and provide a firsthand experience to anchor students' future understanding. I use the postlab questions as formative assessments and to help me plan subsequent lessons. After assessment, I review the postlab questions with the students and clarify misconceptions. Students then continue their study of atomic property patterns through various traditional worksheets, interactive discussion, and small-group practice and later take a summative test to assess their overall learning. Reflections on the lesson In my most recent lesson, almost all students correctly identified the reactivity trend and the ionization energy trend on the first lab. However, very few students gave a correct and complete answer when asked to explain the reasons for the trends using both Coulombic attraction and atomic structure. Therefore, I modified the second lab to have students draw the postlab Bohr diagrams and use them to explain their answers. That proved effective, so I have since modified both sets of postlab questions in the supplementary materials (see "On the web") to elicit the necessary ideas while students are thinking about their data. Conclusion These two lab activities help students to discover periodic table patterns in the properties of atoms. Each lab gives students a concrete representation of an otherwise abstract atomic property. The activities use two classic types of reactions already familiar to many teachers. Both types give extremely consistent results, allowing students to focus on the desired learning goals rather than confusing data. These labs have proven to be an excellent way to begin the study of the periodic table and of its predictive power. Dusty Carroll (dcarroll@lrhsd.org) is a science teacher at Seneca High School in Tabernacle, New Jersey. On the web Student handouts and teacher notes: www.nsta.org/highschool/connections.aspx References NGSS Lead States. 2013. Next Generation Science Standards: For states, by states. Washington, DC: National Academies Press. Trout, L. 2012. POGIL activities for high school chemistry. Batavia, IL: Flinn Scientific.

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Dusty Carroll 2017-08-02 05:10:12 Analyzing chemical reactions to determine trends in ionization energy and electron affinity Some chemical reactions are versatile and can be used with various topics to provide a valid educational experience. Two such reaction types are those of metals with acids and of halogens with alkali metal halides (Figures 1 and 2, respectively, pp.

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Science Teaching Materials - NSTA Press Extras: Argument-Driven Inquiry in Chemistry

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Explore/Explain: Periodic Trends Identification Argument Driven Inquiry Lab 7

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Explore/Explain: Periodic Trends Identification Argument Driven Inquiry Lab 7

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Analyze data of periodic table to make claim

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Explore: Alien family and groups card sort

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Explore: Alien family and groups card sort

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Remove a card or two to allow students the opportunity to consider what the card might look like based on the patterns

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Periodic Table Card Sort - Alien Pictures

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What patterns are there in Pressure, Temp, and Volume? Given these phenomenon, which law best explains? Use the simulation to generate data and create a CER for each phenomenon being studied.

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In this simulation, students will investigate three of the fundamental gas laws, including Boyle's Law, Charles' Law and Gay-Lussac's Law. Students will have the opportunity to visually examine the effect of changing the associated variables of pressure, volume, or temperature in each situation. Also, students will analyze the gas samples at the particle level as well as manipulate quantitative data in each scenario. Finally students will interpret trends in the data by examining the graph associated with each of the gas laws.

This simulation was developed through generous funding provided by Dow Chemical Company, the Sole Founding Partner of AACT.
See accompanying lesson plan

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Classroom Resources | Gas Laws Simulation | AACT

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AACT is a professional community by and for K-12 teachers of chemistry

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Explore: Ionization Energy Side by Side Comparison of Elements

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Explore: Ionization Energy Side by Side Comparison of Elements

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In this simulation, students can investigate the periodic trends of atomic radius, ionization energy, and ionic radius. By choosing elements from the periodic table, atoms can be selected for a side by side comparison and analysis. Students can also attempt to ionize an atom by removing its valence electrons. Quantitative data is available for each periodic trend, and can be further examined in a graph.

This simulation was developed through generous funding provided by the Camille & Henry Dreyfus Foundation.

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Classroom Resources | Periodic Trends: Ionization Energy, Atomic Radius & Ionic Radius | AACT

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In this simulation, students can investigate the periodic trends of atomic radius, ionization energy, and ionic radius. By choosing elements from the periodic table, atoms can be selected for a side by side comparison and analysis. Students can also attempt to ionize an atom by removing its valence electrons.

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What patterns can be identified relating to temperature, pressure, and volume?

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GasSim - a gas law simulation app from ScienceBySimulation

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Requires Flash

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Explore this collection of videos on each element in the periodic table. Featuring Murray Robertson's Visual Elements annimated artwork and videos from the University of Nottingham's Periodic Table of Videos.

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What are periods? Groups? Blocks? Metal? Non Metal?

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The Royal Society of Chemistry's interactive periodic table features history, alchemy, podcasts, videos, and data trends across the periodic table. Click the tabs at the top to explore each section. Use the buttons above to change your view of the periodic table and view Murray Robertson's stunning Visual Elements artwork. Click each element to read detailed information.

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Periodic Table - Royal Society of Chemistry

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Interactive periodic table with element scarcity (SRI), discovery dates, melting and boiling points, group, block and period information.