Photosynthesis Lab - Hour 7 by Jeremy Mohn https://padlet.com/jmohn/odbl040m79nw Group 7 - Light Intensity en-us 2016-10-15 21:02:42 UTC 2025-11-02 05:00:27 UTC hello@padlet.com http://d20uo2axdbh83k.cloudfront.net/20141020/47034972b1207c3982eed5f412f5322b.gif Results jmohn https://padlet.com/jmohn/odbl040m79nw/wish/130937014 Spinach leafs exposed to a lower light intensity took 1748 seconds to rise to the surface, while leafs exposed to a higher light intensity took only 1012 seconds to rise. This shows a slower rate of photosynthesis in leafs exposed to less light because it took them longer to rise. It took the leafs at a lower light intensity longer to rise, because oxygen was not produced as rapidly. Since oxygen is a product of photosynthesis we know that slower production of oxygen indicates slower rate of photosynthesis. In summary, leafs exposed to a higher light intensity have a higher rate of photosynthesis.]]> 2016-10-15 21:02:42 UTC https://padlet.com/jmohn/odbl040m79nw/wish/130937014 Conclusion jmohn https://padlet.com/jmohn/odbl040m79nw/wish/130937015 Our hypothesis: that leaves exposed to a lesser light intensity would have a slower rate of photosynthesis was proved to be true in our experiment. The leaves took longer to rise when exposed to less light showing that the rate of photosynthesis was lower. A possible source of error that may have occurred was different temperatures of sodium bicarbonate. We never measured the temperature of the two liquids and if the temperature was higher in one cup, then that rate of photosynthesis would most likely have been more rapid. Another source of error could of been not getting all the water out of the leaf chads. If not all air was removed then it could cause those leafs to rise too soon. Future purposes this lab could serve is researching what level of light intensity do plants respirate best in. Overall the lab was a success and allowed us to gain knowledge of how light intensity affects the rate of photosynthesis.]]> 2016-10-15 21:02:42 UTC https://padlet.com/jmohn/odbl040m79nw/wish/130937015 Procedure jmohn https://padlet.com/jmohn/odbl040m79nw/wish/130937016
  • Obtain all materials required to perform this lab
  •  Pour the sodium bicarbonate solution into a clear plastic cups to where there is about a 2 centimeters left at the top.  Using a pipette, add one drop of a dilute liquid soap solution to the sodium bicarbonate solution in each cup. This acts as a surfactant and wets the hydrophobic surface of the leaf so they can absorb the water. 
  • For the Control: Place the cup of water on top of the light pad. 
  • Using a hole punch, create 16 uniform leaf discs (8/cup), *makes sure to avoid the leaf vein*.
  • In order for the experiment to work you must get all the air out of the chads so that they can sink to the bottom: 
    1.  Remove the piston from the syringe and place the 9 leaf chads into each syringe barrel. 
    2.  Place the piston back in the syringe, but be careful not to crush the leaf disks. Push the piston in, to a point where only a small volume of air and leaf chads remain in the barrel.
    3.  Pull 5mL of the distilled water from the cup. Tap each syringe to get the chads to rise and be suspended in the syringe. In order to make sure that no air remains move the piston to get rid of air from the plunger * it's okay if a little water squirts out*.
    4.  Now create the vacuum by pressing your finger over the syringe opening, and simultaneously drawing back the piston. Hold the syringe in this position for about 10 seconds. While holding the piston back, swirl the leaf disks to suspend them in the solution. Now release the vacuum by letting the plunger spring back. This will cause the  solution to fill the air spaces, which will cause the leaf chads to sink in the syringe. If the leaf chads don't sink the first time, You will have to repeat this step a couple of times in order to get the disks to sink. 
  •  Now you can pour the disks into the sodium bicarbonate cup by just removing the piston from the syringe and letting the contents pour in.
  •  Record your findings, and remember to use the time value of when 50% of the leaves rise. After obtaining your results use the Excel to graph.
    • ]]>     2016-10-15 21:02:42 UTC https://padlet.com/jmohn/odbl040m79nw/wish/130937016     Research Question jmohn https://padlet.com/jmohn/odbl040m79nw/wish/130937017 How does a lower intensity of light affect the rate of photosynthesis in spinach?]]> 2016-10-15 21:02:42 UTC https://padlet.com/jmohn/odbl040m79nw/wish/130937017 Hypothesis/Prediction jmohn https://padlet.com/jmohn/odbl040m79nw/wish/130937018 Hypothesis: Decreasing the light intensity will lower the rate of photosynthesis in spinach.

    Prediction: If spinach are exposed to a lower intensity of light, then their rate of photosynthesis will decrease.
    ]]>     2016-10-15 21:02:42 UTC https://padlet.com/jmohn/odbl040m79nw/wish/130937018     Graph jmohn https://padlet.com/jmohn/odbl040m79nw/wish/130937019 2016-10-15 21:02:42 UTC https://padlet.com/jmohn/odbl040m79nw/wish/130937019 Effect of Light intensity on photosynthesis in spinach jmohn https://padlet.com/jmohn/odbl040m79nw/wish/131551932 Names: David Hickerson, Mahmood Khatib, Gage Hall]]> 2016-10-18 16:49:02 UTC https://padlet.com/jmohn/odbl040m79nw/wish/131551932