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“When the statue was originally assembled, it was dull brown color, reflecting the natural color of it’s copper plates. Over the next 30 years, though, it slowly turned to the green color you see today.”

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This video shows how the plant closes up and the fly slowly dies and provides enough nutrients for the Venus Fly Trap.

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Giant Venus Flytrap Plant eating insect Fly gets eaten by plant

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This article talks about how oxidation over time change the look, and material.

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(3) Oxidation stability (ASTM D4742 method at 160°C).

Oxidation stability was evaluated by the thin film oxygen uptake test TFOUT (ASTM D4742) at 160°C. As shown in Table 3.7, the borate micelles showed better oxidation stability compared to that of carbonate micelles in the same detergent type. For example, oxidation stability of a micellar borate-sulfonate system from 180 min decreased to 160 min for micellar carbonate-sulfonate. The good oxidation stability obtained by micellar borate-detergents might be explained by the action of boric acid liberated by the reaction of borates and oxidative products. The boric acid formed during oxidative degradation then acts as an hydroperoxide deactivator (Yamada et al., 1992).

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URL: https://www.sciencedirect.com/science/article/pii/S0167892203800184

Test E

Oxidation field test. The results were obtained by Fourier transform infra-red (FTIR) spectroscopy. In the sump oil field test temperature was from 90 to 110°C, and in the oil bench test temperature was 170°C. In both field and bench tests data indicates that the magnesium sulfonate-containing oil gave higher oxidation level, and the calcium sulfonate-containing oil gave lower oxidation levels. Each of the evaluated detergent types has its strengths and weaknesses. Some detergents which have good TBN retention are less effective in neutralizing acids, and may cause lubricants to be less oxidatively stable.

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V.A Oxidation States

The oxidation states of the actinide elements are listed in Table VI. Unlike the lanthanide elements, for which the dominant oxidation state is +3, the actinides exhibit a broad range of oxidation states, ranging from +2 to +7 in solution. The proximity of 5 f, 6 d, and 7 s energy levels in the lighter actinides results in a variety of oxidation states up to +7. The stability of the higher oxidation states decreases with increasing atomic number. From americium on, a more lanthanide-like behavior is exhibited. The most stable oxidation state of the heavier actinides with the exception of No is +3; however, in contrast to the analogous lanthanides, the divalent oxidation state appears well before the end of the actinide series. Thus, in comparison with the analogous 4 f electrons, the 5 f electrons in the latter part of the actinide series appear more tightly bound.

With the exception of thorium and protactinium, all of the actinide elements show a +3 oxidation state in aqueous solution. A stable +4 state is observed in the elements thorium through plutonium and in berkelium. The oxidation state +5 is well established for the elements protactinium through americium, and the +6 state is well established in the elements uranium through americium. The oxidation state +2 first appears at californium and becomes increasingly more stable in proceeding to nobelium.

For any oxidation state, the ionic radii decrease regularly with increasing atomic number as a consequence of the decreased shielding by f electrons of the outer valence electrons from the increasing effective nuclear charge. This actinide contraction is very similar to the corresponding lanthanide contraction. Table VII summarizes crystallographic ionic radii of lanthanide and actinide ions for coordination numbers 6 and 8.

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4.17.5.1.1 Metallic coatings

Oxidation of aluminum-modified Zr alloy surfaces (synthesized by magnetron sputtering of aluminum and subsequent thermal annealing) at 800°C in steam for 120 min displayed better oxidation resistance with average oxide layer thicknesses of ~0.7 µm (around 8 µm for un-modified specimens). However, the oxide layer was slightly thicker for treated specimens after oxidation at 1000°C. The poor oxidation performance of the coated surfaces is likely attributed to the formation of brittle intermetallics (see calculated phase diagram of Zr-Al in Fig. 17; Zr-Cr, Zr-Fe and Mo-Zr systems are also given) and surface cracks, preventing the growth of a continuous and uniform alumina scale.

The oxidation performance of thick Si coatings (up to 150 µm) fabricated by plasma spray with subsequent laser beam scanning treatment was investigated at 1200°C in steam. The coated samples displayed improved oxidation resistance with ~60% mass gain compared to uncoated ones after exposure for 2000 s. However, here the coatings were too thick and as aforementioned, pure Si is unstable during normal operation.

Steam oxidation performance of Cr coatings, deposited by diverse methods, have been intensively examined. 23,31,33,35,36,41,42-44,46,47,51-53 Generally, the high-temperature oxidation kinetics of Cr-coated Zr alloys is significantly reduced compared to uncoated alloys up to 1200°C relevant for LOCA scenarios. The coatings form a protective Cr ₂O ₃ scale during oxidation, demonstrating acceptable performance even under beyond design-basis conditions below the Zr-Cr eutectic temperature (1332°C, as shown in Fig. 17(b)). Fig. 18 compares the oxidation performance and mechanical behavior of PVD Cr coated and uncoated Zr alloys. Clearly, the oxide scale thickness on the Cr coating layer is one order of magnitude lower than that on bare Zr alloys during oxidation at 1200°C in steam, Fig. 18(c). Consumption of the coatings is determined by two combined processes, i.e., surface oxidation and inward diffusion into the substrate, as displayed in Fig. 18(d). The 12-15 µm Cr coating deposited by PVD can delay the oxidation of the Zr alloy substrate for approximately 5 h at 1100°C or 1 h at 1200°C in steam. It is necessary to point out that at high water vapor partial pressure (>10 kPa) formation of volatile chromium oxyhydroxides becomes prominent, which further limits its protective capability to lower temperature (~1040°C). The Cr-coated samples also demonstrated negligible reduction of residual strength and ductility before the complete consumption of the metallic Cr layer, Fig. 18(e), and improved ballooning and rupture resistance. In addition, the chromium coatings revealed high adherence without peeling including at the vicinity of the burst opening. The amount of hydrogen picked up by the cladding was significantly reduced simultaneously due to the existence of the Cr ₂O ₃ barrier. Similarly, enhanced oxidation and mechanical performances were reported for Cr coatings fabricated by other methods. However, during long-term scenarios inward diffusion of Cr could cause hardening and enhanced embrittlement of the cladding due to formation of brittle intermetallics. Han et al. found that the completely oxidized Cr coating can be reduced by the Zr substrate, revealing more complicated oxidation mechanisms. In case of cold sprayed coatings, accelerated growth of initially existing cracks and bending of the coated tubes were observed during oxidation. Occurrence of these undesirable features needs to be addressed and avoided via coating optimization in the future.

Al- and/or Si-containing Cr alloys such as CrAl and CrAlSi were also considered as protective coatings, aiming to improve the oxidation resistance relative to pure Cr coatings. A CrAl (30 wt% Al) coating layer deposited via a laser coating process resulted in significant mixing of CrAl coating metal with the Zr substrate. The coatings demonstrated poor oxidation resistance because of considerable interdiffusion and formation of intermetallic compounds. CrAl coatings deposited by PVD displayed much better oxidation performance. A metastable alumina layer developed on the CrAl coatings with Al composition over 43 at% during oxidation at 700°C in steam. A 1 µm oxide layer (mainly Cr ₂O ₃) formed on CrAl (15 wt%)-coated cladding after oxidation at 1200°C for 3000 s in steam and water quenched. Improved rupture resistance and post-quench ductility were also seen for coated samples. Decreased oxidation rates of PVD CrAlSi coated specimens compared to bare Zr alloys up to 1200°C were reported. However, coating constituent elements (primary Al or Si) diffused substantially into the substrate and formed intermetallic phases with the Zr alloy substrate during oxidation.

Alumina-forming FeCrAl alloys (adequate addition of Cr and Al) are well known for their excellent high-temperature oxidation resistance and thus have been intensively investigated as protective coatings on Zr alloys. Formation of a protective alumina layer was confirmed during oxidation at relatively low temperature, such as 700°C in steam. However, rapid degradation of the coatings without protection was seen once the oxidation temperature exceeds the Fe-Zr eutectic reaction temperature (around 930°C, Fig. 17(c)). Formation of interfacial intermetallic compounds at lower temperatures also embrittles the coated cladding. Many efforts now attempt to identify a suitable interlayer as diffusion barrier. 64,74,82,95,154

Oxidation of zirconium silicide (Zr ₂Si, ZrSi, and ZrSi ₂) coatings revealed that ZrSi ₂ possesses the best anti-oxidation behavior via formation of an oxide layer consisting of nanocrystalline SiO ₂ and ZrSiO ₄ in an amorphous Zr-Si-O matrix at 700°C in air. However, the coatings have very limited improvement at higher temperatures. The incorporation of ZrO ₂ into the scale during oxidation likely compromises the protective nature of the coatings.

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4.08.7.4 Oxidation

Oxidation tests for 9Cr-ODS and 12Cr-ODS steels were performed using pickled specimens in a controlled atmosphere of dry air. Weight measurement to evaluate the degree of oxidation was performed at intervals of 50, 100, 400, 1000, and 2000 h, at temperatures of 650, 750, and 850 °C. The results of the measured weight gain due to oxidation at 750 °C are shown in Figure 36. For 9Cr-ODS and 12Cr-ODS steels, the weight gain due to oxidation was quite small and comparable to that of PNC316 containing 17 wt% Cr. Their weight gain is limited to below 0.1 mg mm −2. On the other hand, a quite large oxidation of 0.8 mg mm −2 was observed in PNC-FMS. The measured results on SUS430, which show a greater weight gain than that of ODS steels, show that advanced oxidation resistance is attained with ODS steels, even when compared to higher 17 wt% Cr containing stainless steel.

The element distribution obtained by Electron probe microanalysis (EPMA) showed a scale consisting of Fe-rich oxide in the outer layers and Cr-rich oxide in the inner layers. At the interface between ODS steel and the oxide scale, there was a thin layer (a few micrometers) of further Cr-enriched oxide. Raman spectroscopy measurement indicated that the outer Fe-rich and inner Cr-rich layers correspond to α-Fe ₂O ₃ and spinel type (Fe, Cr) ₃O ₄, respectively. It was also confirmed that α-Cr ₂O ₃ is formed at the matrix-scale interface.

In oxidation tests, Fe, which is a major constituent in steel, tends to be easily oxidized at an early stage, but further oxidation can be suppressed by the formation of a protective α-Cr ₂O ₃ layer. This α-Cr ₂O ₃ formation is generally controlled by the rate at which Cr is supplied to the reaction front. It is known that a high Cr content in steel, as well as an increasing diffusion flux through the grain boundary, that is, finer grains, accelerates both the Cr supply and the formation of α-Cr ₂O ₃. A short-term oxidation test, whose results are shown in Figure 37, was conducted to investigate the mechanism of suppressing oxidation in ODS steels. The decrease in oxidation in fine grain 12Cr-ODS ferritic steel can be attributed to the enhanced rate at which Cr was supplied throughout the accelerated grain boundary diffusion. In both cases of fine/large grains in 12Cr-ODS steels, Raman spectroscopy detected protective α-Cr ₂O ₃ at the interface between the matrix and scale. Comparing 12Cr-ODS large grain and PNC-FMS, the Cr content is similar, and the grain size is rather smaller in PNC-FMS. Nevertheless, protective α-Cr ₂O ₃ cannot be detected by Raman spectroscopy, and oxidation is enhanced in PNC-FMS, implying that the suppression of oxidation in 12Cr-ODS with large grains could be due to the effects of the Y ₂O ₃ oxide particles themselves. Chen et al. showed some TEM images of Y-rich oxides on grain boundaries that may be part of the explanation.

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Bomb Oxidation Tests

Oxidation of oil can be accelerated by substituting oxygen for air and performing the test under elevated pressure, which increases the solubility of oxygen in oil. A 'bomb' is the term used to describe a mechanically strong enclosed vessel specifically designed for containing the mixture of oxygen and oil during a test. Since the reaction products are largely vapour or gas and the oxygen is pressurised, a robust vessel is required to withstand the stresses that may be generated by an unexpectedly reactive oil.

An apparatus used to determine the oxidation stability of greases is illustrated schematically in Figure 9.8 while the test procedures are specified in IP 142/85. The vessel is pressurized with air or oxygen in order to raise the severity of the test and shorten its duration. The relative oxidation data is obtained from the decline in gas pressure as the grease sample consumes oxygen to form nongaseous oxidation products. With most lubricants, there is an 'induction period' where very little visible oxidation occurs. Once the induction period is passed, then oxidation appears to proceed rapidly and the pressure in the bomb declines sharply. The time required for the specified pressure loss to occur is used as a measure of the oxidation stability of greases.

To determine an oxidation stability of lubricating oils, a more sophisticated test, called the 'rotating bomb oxidation test', is used. The details of the test are described in IP 229/93 and ASTM D 2272 standards. The rotating bomb apparatus consists of a glass vessel inclined at an angle of 30° to the horizontal while being rotated by an electric motor. The purpose of this arrangement is to maintain a continuous circulation of the lubricant around a metal catalyst while being surrounded by a pressurized oxygen or air atmosphere. The metal catalyst is in the form of a wire coiled around the inside of the glass vessel. The circulation of lubricant ensures uniform access to oxygen and catalyst by every part of the lubricant sample. During the test, the oil and oxygen are added to the glass vessel ('bomb') and the oxygen pressure is raised to 620 [kPa]. The bomb is then heated to 150 °C by immersion in a thermostatic bath and rotated at 100 [rpm]. Water and a solid copper catalyst are also added into the bomb to provide a closer simulation of operating conditions for a real lubricant. The induction time, manifested by a rapid drop in oxygen pressure, is used as a relative measure of oxidation stability of lubricating oils. The test is considered complete when the pressure drops by 175 [kPa]. The rotating bomb oxidation apparatus is illustrated schematically in Figure 9.9.

The rotating bomb oxidation test can typically require 2 to 30 hours for completion [22] and while much quicker than the tests at atmospheric pressure, this length of time still poses some difficulties for the wider applications of this test in machine condition monitoring. Furthermore, complex formulated oils such as engine oils containing Zinc Dialkyl Dithiophosphate (ZnDDP) do not show an easily determined, distinct decline in pressure and so are difficult to assess by this technique. The test is found to be most effective for oils containing aromatic amines and phenolic amines as antioxidants, which are typically used for turbine oils and this is where the test is most widely used [24].

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3.1 NO oxidation by O₂

3.1.1 Influence of the catalyst nature

Oxidation of NO by O ₂ in the presence of water, CO ₂ and SO ₂ strongly depends on the nature of the catalyst (Fig. 1). With rhodium or iridium and more particularly with palladium or copper NO oxidation is very limited below 400 °C. The only catalyst which is very active even at low temperature is platinum.

3.1.2 NO oxidation over Pt/Al₂O₃

3.1.2.1 Influence of the space velocity

3.1.2.2 In the presence of reductants

As in the absence of reductant, NO ₂ concentration goes through a maximum when temperature increases, but this maximum is clearly below that observed without reductant. This can be explained if we consider that the thermodynamic equilibrium for NO oxidation should more appropriately be expressed with the reactor outlet temperature than to the reactor inlet temperature: under adiabatic conditions the temperature increase is about 120 °C for the combustion of 6000 ppmC hydrocarbon. This temperature shift is well suited to explain the NO oxidation curve in the presence of ethylene. It is less adapted in the presence of n-decane probably because decane oxidation is diffusion limited and reaches total conversion only at high temperature: NO oxidation is not at equilibrium.

The temperature shift for NO oxidation in the presence of reductants could have several origins. NO ₂ could not be formed on the catalyst surface until the reductant concentration in the adsorbed state is very low or NO ₂ could be formed but rapidly reduced by hydrocarbon or carbon monoxide. NO ₂ reduction could occur on the catalyst surface between adsorbed species or in gas phase by homogeneous reaction with the reductant.

Although NO ₂ can be formed at low temperature on platinum, it is not detected in the presence of a reductant. The NO oxidation sites can be blocked when their covering by reductant is high or NO ₂ adsorbed species are reduced in presence of carbon monoxide and hydrocarbons before their desorption. Therefore the absence of NO ₂ in the gas phase does not necessarily means that it is not present as adsorbed species.

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Abstract

Oxidation of gaseous metallic mercury by hydrogen chloride was studied over different oxide catalysts such as CuO, Fe ₂O ₃, and CoO nano-particles as well as V ₂O ₅, NiO, CuO, MoO3, and WO ₃ supported on TiO ₂. Among the catalysts tested, CuO nano-particles showed the highest catalytic activity and were further investigated as a candidate for industrial applications. The catalyst layer composed of CuO nano-particles, which were fixed to the steel plate by the heat-resistant paint, were prepared and confirmed to be also active for mercury oxidation by a trace amount of HCl.

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2.23.4 Oxidation of Cladding

Zirconium, the main component of the cladding material, reacts with water. The reaction is described by the following chemical equation:

Zr+2 H 2 O→ZrO 2+2 H 2+586 kJ mol−1

Elemental reactions as well as migration of the atoms, ions, and electrons in the reaction are schematically shown in Figure 6. Oxygen generated at the surface by the reaction diffuses into the internal part of the cladding. According to the gradient of oxygen concentration ( Figure 7), ¹⁸ an oxide (ZrO ₂) layer and a layer of α-phase with a high content of oxygen (α-Zr(O)) grow on the β-phase during oxidation above about 1000 °C as shown in Figure 8. The β-phase transforms back into the α-phase during cooling and quenching with higher rates. The microstructure after the fast cooling is quite different from the initial as-fabricated microstructure. Thus, the α-phase is called 'prior-β-phase' or 'transformed β-phase' and shows the basket-wave (Widmanstätten) structure.

The oxide layer and the α-Zr(O) layer are brittle. Therefore, ductility of the cladding is controlled by thickness and ductility (oxygen content) of the prior-β-phase layer. Hydrogen is generally swept away under steam-flow conditions that are normally expected in the reactor core. However, a large amount of hydrogen is absorbed in the cladding if the partial pressure of hydrogen is high under stagnant steam conditions and 'breakaway' oxidation conditions. 19,20 Once the breakaway oxidation occurs, the oxidation rate significantly increases. The mechanism of the breakaway oxidation has not been always clarified. However, the oxide layer has laminar structures and radial cracks, and the oxidation occurs near the α + β-phase temperature region for a longer time (at 500-1050 °C for >3600 s). Therefore, it may be connected with phase transitions and the subsequent stress generated in the oxide layer.

The cladding oxidation is very important for safety in terms of the following issues:

*

The cladding is embrittled when severely oxidized.

*

The oxidation is an exothermic reaction which is a source of the core heating.

*

The oxidation generates hydrogen which may be a source of explosion inside the containment vessel.

Hence, oxidation kinetics has been extensively studied to increase the accuracy of the safety analysis. Oxidation of zirconium alloys is controlled by diffusion of oxygen in the oxide layer and it obeys a parabolic rate law above about 1000 °C. Namely, the oxidation is described by the following equation.

where Δ w is the reaction amount (weight increase or oxide layer growth), K is the reaction rate constant, and t is the oxidation time, (see also Chapter 5.03, Corrosion of Zirconium Alloys).

Figure 9 compares the temperature dependences of the reaction rate constant, which were obtained by various researchers, ²¹⁻²⁵ for the oxidation of Zircaloy cladding in the temperature range above 1000 °C. The reaction rate exponentially increases with the temperature, and therefore the temperature dependence is described by an Arrhenius-type equation:

where A is a preexponential factor, Q is the activation energy in J mol −1, T is the temperature in K, and R is the gas constant (8.314 J mol −1 K −1).

The oxidation is very fast above 1200 °C, and the cladding of 0.6 mm thickness completely transforms to the oxide and the α-Zr(O) layers at 1200 °C within about 1800 s or at 1300 °C within 900 s. The figure shows that the reaction rates agree very well except for the Baker-Just equation. It is known that the Baker-Just equation overestimates the reaction, but the equation is often used for the safety analysis to obtain conservative results. The temperature dependence of the oxidation rate constant shows discontinuities at about 1000 and 1500 °C. It is considered that the discontinuities are related to the phase structure changes of oxide from monoclinic to tetragonal and from tetragonal to cubic, respectively. The oxidation obeys a cubic rate law for longer term oxidation at temperatures below 1000 °C. 25,26

In the oxidation test with corroded cladding, it was observed that no additional oxidation is observed for shorter times, an additional oxide is locally formed at cracked positions of the corrosion layer for longer times, and finally the high-temperature oxide grows uniformly beneath the corrosion layer ( Figure 10). ²⁷ These results show that the corrosion layer has a protective effect for the high-temperature oxidation, that high-temperature oxidation initiates at cracks in the corrosion layer, and that this barrier effect is maintained until an additional oxide layer by high-temperature oxidation is uniformly formed beneath the corrosion layer. The protective effect becomes smaller for longer times and at higher temperatures. It has been observed that fine cracks are generated in the corrosion layer due to ballooning during the heat-up phase and the oxide is uniformly formed beneath the corrosion layer even in the shorter period. Therefore, the protective effect of the corrosion layer is not expected in actual LOCA conditions where the cladding balloons. ²⁸

Influence of hydrogen on the oxidation kinetics has been also studied. The oxidation kinetics can be changed by prehydriding and the effect is different depending on oxidation temperature, time, and hydrogen concentration. However, the effect is so small (<5%) in the realistic conditions (<800 ppm and <300 s) that it can be actually neglected in the safety evaluation. 29,30

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1 Introduction

Oxidation of the relatively inert C-H bond of hydrocarbons is one of the most desirable but challenging reactions from an academic and industrial point of view. Vanadium phosphorous oxide (VPO) catalysts are used commercially for the selective oxidation of n-butane to maleic anhydride [1] and it has also been shown that this catalyst can be effective for other selective oxidation reactions including the ammoxidation of propane, oxidation of pentane to phthalic anhydride and oxidation of toluene to benzaldehyde [2].

The VPO catalysts are very sensitive to their structural and morphological characteristics [3] and accordingly we have been working on the synthesis of new, modified and mesostructured VPO phases [4]. In this context we have recently demonstrated a novel approach involving exfoliation of the layered VPO phases in suitable solvents followed by their surfactant assisted organization into a mesostructured phase [5]. In the present work, the exfoliation concept has been used to prepare novel dispersed VPO phases by exfoliating VOPO ₄.2H ₂ O in 2-propanol followed by its dispersion on alumina with different VPO: alumina ratios and evaluating the catalytic activity of these dispersed phases for the selective oxidation of cyclohexane.

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Oxidation stability was evaluated by the thin film oxygen uptake test TFOUT (ASTM D4742) at 160°C. As shown in Table 3.7, the borate micelles showed better oxidation stability compared to that of carbonate micelles in the same detergent type. For example, oxidation stability of a micellar borate-sulfonate system from 180 min decreased to 160 min for micellar carbonate-sulfonate.

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Wonder opilice said “Once the Venus flytrap snaps closed, it secretes digestive enzymes. These break down the trapped insect into a soupy substance.” This shows it is a chemical change.

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The digestion system works by acid in the stomach breaking down food into different substance which you deposed out of you body.

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The human digestive system - National Geographic Kids

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Take a journey through the human digestive system and discover how your mouth, stomach, intestines, pancreas and other body parts hep break down your food!

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The Statue of Liberty is a famous landmark with an iconic blue-green color. However, it wasn't always green. When the Statue was unveiled in 1886, it was a shiny brown color, like a penny. By 1906, the color had changed to green. The reason the Statue of Liberty changed colors is that the outer surface is covered with hundreds of thin copper sheets. Copper reacts with the air to form a patina or verdigris. The verdigris layer protects the underlying metal from corrosion and degradation, which is why copper, brass, and bronze sculptures are so durable.

Most people know copper reacts with air to form verdigris, but the Statue of Liberty is its own special color because of its unique environmental conditions. It's not a simple single reaction between copper and oxygen to produce a green oxide like you might think. The copper oxide continues to react to make copper carbonates, copper sulfide, and copper sulfate.

There are three main compounds that form the blue-green patina: Cu ₄SO ₄(OH) ₆ (green); Cu ₂CO ₃(OH) ₂ (green); and Cu ₃(CO ₃) ₂(OH) ₂ (blue). Here's what happens:

Then the copper(I) oxide continues to react with oxygen to form copper oxide (CuO):

At the time the Statue of Liberty was built, the air contained a lot of sulfur from air pollution produced by burning coal:

The CuS reacts with carbon dioxide (CO ₂) from the air and hydroxide ions (OH⁻) from water vapor to form three compounds:

The speed at which the patina develops (20 years, in the case of the Statue of Liberty) and color depends on the humidity and air pollution, not just the presence of oxygen and carbon dioxide. Patina develops and evolves over time. Nearly all the copper in the Statue is still the original metal, so the verdigris has been developing for over 130 years.

You can simulate the patination of the Statue of Liberty. You don't even need to wait 20 years to see results. You will need:

copper pennies (or any copper, brass, or bronze metal)

vinegar (dilute acetic acid)

salt (sodium chloride)

1. Mix together about a teaspoon of salt and 50 milliliters of vinegar in a small bowl. The exact measurements aren't important.

2. Dip half of the coin or another copper-based object into the mixture. Observe the results. If the coin was dull, the half you dipped should now be shiny.

3. Place the coin in the liquid and let it sit for 5-10 minutes. It should be very shiny. Why? The acetic acid from the vinegar and sodium chloride (salt) reacted to form sodium acetate and hydrogen chloride (hydrochloric acid). The acid removed the existing oxide layer. This is how the Statue may have appeared when it was new.

4. Yet, chemical reactions are still happening. Don't rinse off the salt and vinegar coin. Let it dry naturally and observe it the next day. Do you see the green patina forming? The oxygen and water vapor in the air are reacting with the copper to form verdigris.

When the Statue first turned green, people in authority decided it should be painted. The New York newspapers printed stories about the project in 1906, leading to a public outcry. A Times reporter interviewed a copper and bronze manufacturer, asking whether he thought the statue should be repainted. The company's vice president said that painting was unnecessary since the patina protects the metal and that such an act might be considered vandalism.

Although painting the Statue of Liberty has been suggested several times over the years, it has not been done. However, the torch, which was originally copper, corroded after a renovation to install windows. In the 1980s, the original torch was cut away and replaced with one coated with gold leaf.

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The Statue of Liberty is a famous landmark with an iconic blue-green color. However, it wasn't always green. When the Statue was unveiled in 1886, it was a shiny brown color, like a penny. By 1906, the color had changed to green.

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Table 3 - Stella, Beckett, Anthony, Quinn

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Table 3 - Stella, Beckett, Anthony, Quinn

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Digestive enzymes are substances produced by our bodies that help us to digest the foods we eat. These enzymes are secreted by the various parts of our digestive system and they help to break down food components such as proteins, carbohydrates, and fats. This breakdown allows the nutrients from foods to be absorbed into our bloodstreams so that they can support the functioning of all of the cells in our bodies.

The Release of Digestive Enzymes

Digestive enzymes are released in both anticipations of food and in response to food. This means that just thinking about or looking at food is enough to get your juices flowing! As we smell and eventually taste our food, the number of enzymes that are being secreted increases.

Enzymes are ​secreted from our salivary glands, and then from the cells lining our stomach, pancreas, and large and small intestines. Different types of enzymes are secreted depending on the types of foods that we eat.

Our bodies produce many different types of digestive enzymes to help our bodies to take advantage of the various nutrients found within the foods we consume. Here are examples of some of the more prevalent types of enzymes:

Amylase is a digestive enzyme essential for our digestion of carbohydrates, as amylase breaks down starches into sugars. Amylase is secreted by both our salivary glands and from our pancreas. The measurement of amylase levels in the blood is sometimes used as an aid in diagnosing various pancreas or other digestive tract diseases.

Lactase is a type of enzyme that breaks down the sugar, lactose, found in dairy products. Supplemental lactase may be used to assist people who are lactose intolerant to digest dairy products.

Lipase is the enzyme responsible for the breakdown of fats that we consume. Specifically, lipase breaks fats into fatty acids and glycerol (simple sugar alcohol). Within your body, lipase is produced in small amounts by your mouth and stomach, and in larger amounts by your pancreas.

Maltase is secreted by the small intestine and is responsible for breaking down maltose (malt sugar).

Proteases are digestive enzymes that break down proteins into amino acids. Here are the major types of proteases found within the human digestive tract:

Sucrase is secreted by the small intestine where it breaks down sucrose into the simpler sugars of fructose and glucose.

Supplements

There are a wide variety of health conditions that interfere with the secretion of sufficient amounts of digestive enzymes for full digestion of foods. In such a case a person might benefit from taking a digestive enzyme supplement. One of the areas in which digestive enzyme supplements are most helpful is for people who have chronic pancreatitis. For these individuals, digestive enzyme supplements not only help with digestion but also can help to ease the pain associated with the disease.

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Article Sources

Keller, J. & Layer, P. "Human pancreatic exocrine response to nutrients in health and disease" Gut 2005 54:1-28.

Minocha, A. & Adamec, C. (2011) The Encyclopedia of the Digestive System and Digestive Disorders (2nd Ed.) New York: Facts on File.

Roxas, M. "The Role of Enzyme Supplementation in Digestive Disorders" Alternative Medicine Review 2008 13:307-313.

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Why Enzymes Are an Important Part of Your Digestive System

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Digestive enzymes are substances produced by our bodies that help us to digest the foods we eat. These enzymes are secreted by the various parts of our digestive system and they help to break down food components such as proteins, carbohydrates, and fats.

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Table 3 - Beckett, Quinn, Anthony, Stella

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Table 3 - Beckett, Quinn, Anthony, Stella

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“Once the Venus flytrap snaps closed, it secretes digestive enzymes. These break down the tapped insect into a soupy substance.”
This shows the chemical change because it went from a fly to a soupy substance

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Venus Flytrap Digestion- Beckett, Quinn, Anthony, Stella 

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Venus Flytrap Digestion- Beckett, Quinn, Anthony, Stella 

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This video talks about  the chemical change called oxidation or tarnish, and how weathering can causes this to happen.  Also this is what happen to the Statue Of Liberty

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What is TARNISH? What does TARNISH mean? TARNISH meaning, definition & explanation

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Wasps building nests are a chemical change because queen wasp use their saliva and break down near materials to a pulp. The pulp can be molded with the help of construction wasps toy form a hive such as shown in the article “ With a mouth full of wood fibers, the queen uses the saliva in her mouth to break down the wood fibers until they form a soft paper pulp.” Another reason this is a chemical change because the saliva is a good comparison to a human digestion system where the acid is in the stomach break down the food.

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Wasps, like hornets, yellow jackets, and paper wasps, are aerial menaces who are annoying at best and can cause you a lot of pain with their sting at worst. If you've noticed wasps around your home, it's likely that there's a nest somewhere on your property. Wasps nests are made with similar materials to each other, but they vary widely in size, shape, and location depending on the species that made them. Typically, however, you'll see nests that resemble honeycombs or an enclosed paper structure. These small, sturdy nests can hold up to 10,000 individuals at their peak, all of which can cause you and your home a lot of strife.

Follow along as we detail general wasp nest facts, including how wasps build their nests, what they are made out of, and more.

Where Do Wasps Usually Build Their Nests?

Have you ever noticed an uptick of wasps around your home when it starts to warm up? It's likely that your house has a lot of high areas that are tucked away, like eaves and porch overhangs. Wasps favor these nesting spots because they are much less likely to interact with people, which helps to protect them, their queen, and their offspring.

Other types of wasps species - such as hornets, yellowjackets, and mud daubers - build their nests in even harder to get to places. Hornets build football-shaped nests that are frequently located on high tree branches, so if your yard has a lot of trees, be sure to look out for telltale signs of a nest. Yellowjackets, on the other hand, build their nests underground.

Mud daubers, which are several species of slightly elongated wasps that construct their nests using mud, have even more interesting nests that can be located around homes. The organ pipe mud dauber builds its nest in the shape of a cylindrical tube resembling an organ pipe and it's commonly found on vertical or horizontal areas like walls, overhangs, and bridges.

Black and yellow mud daubers build one-cell nests containing one egg each and multiple nests are usually clumped together. The metallic-blue mud dauber is known for either building a new mud nest or refurbishing the abandoned nest of another species. These two species' nests commonly occupy the same barns and porches as each other.

What Do Wasps Use to Build Their Nests?

There are a lot of substances wasps use to build their nests but the most common (and abundant) material is paper pulp. They create this material using raw wood and their own saliva. To begin the nest, the queen wasp selects a suitable site and searches for sources of wood fiber, such as trees, logs, fences, houses, or even cardboard boxes. Using her jaws, the queen then scrapes off bits of wood fiber to use.

With the wood product in her mouth, the queen's saliva breaks down the wood fibers until they form a soft paper pulp that she can then manipulate. Eventually, she will begin constructing the nest at the building site. Once worker wasps start to become fully grown, which takes about three weeks, they will assist the queen in expanding the nest.

How Long Does It Take to Build a Wasp Nest?

Nests are generally always under construction throughout the spring and summer as the colony continues to grow, so technically, a fully realized nest takes about 4-6 months to complete. In the fall, the nests reach their peak size and are then abandoned because only a fertilized queen can survive the winter.

During the lifecycle of a wasp nest, any part of it can happen inside or around your home. This can, of course, cause damage to the structure of the property and lead to expensive repairs. Additionally, you or your loved ones could happen upon a nest and get stung. If you notice that there's a wasp nest in or around your house, call Insight Pest Solutions today. Our team is uniquely qualified to get rid of wasps and other common pests safely and without using harmful chemicals.

Learn more about our wasp removal services or schedule a free consultation online today!

Posted in: Uncategorized

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How Do Wasps Build Their Nests? | Insight Pest Solutions

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Wasps, like hornets, yellow jackets, and paper wasps, are aerial menaces who are annoying at best and can cause you a lot of pain with their sting at worst. If you've noticed wasps around your home, it's likely that there's a nest somewhere on your property.

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There are two types of erosion, wind and water. You can tell which is which by one simple thing, if there is water, an ocean, or river near the erosion then it was caused by water, if not it is wind erosion.

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Chemical Change: Eloise, Hannah, and Nathan

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Chemical Change: Eloise, Hannah, and Nathan

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Our change is chemical change because the text states “It was science. A natural weathering process-called oxidation-took place when air and water reacted with the copper plates.”

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Venus Flytrap Digestion Time Lapse | Compilation

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This photo shows how things like water and rocks can push against other natural landforms to cut it back, and create a physical change.

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Venus flytrap ( Dionaea muscipula) is a carnivorous plant. Catching its prey, mainly insects, with a trapping structure formed by its leaves, the plants' glands secrete an enzyme to decompose the prey and take up the nutrients released.

Although postulated since Darwin's pioneering studies, these secretory events have not been measured and analysed until now: An international team of researchers headed by Rainer Hedrich, a biophysicist from Julius-Maximilians-Universität (JMU) Würzburg in Bavaria, Germany, present the results in the journal PNAS.

When a prey tries to escape the closed trap, it will inevitably touch the sensory hairs inside. Any mechanical contact with the hairs triggers an electrical signal that spreads across the trap in waves. From the third signal, the plant produces the hormone jasmonate; after the fifth signal, the digestive glands that line the inside of the traps like turf are activated.
Glands secrete acidic vesicles to decompose prey
What happens next in the gland cells? They increasingly produce membranous bubbles filled with liquid (secretory vesicles) and give off their content. This happens after mechanical stimulation of the sensory hairs but also when the glands come into contact with the hormone jasmonate. The entire process depends on calcium and is controlled by a number of specific proteins.

Moreover, genes are activated in the glands: "We assume that they provide for the vesicles being loaded with protons and chloride, that is hydrochloric acid," Hedrich explains and he adds: "We used ion-sensitive electrodes to measure that repeated touching of the sensory hairs triggers the influx of calcium ions into the gland. The rising calcium level in the cytoplasm causes the vesicles to fuse with the plasma membrane, similarly to the neurotransmitter secretion of neurons. The influx of calcium is followed by the efflux of protons and chloride after a time delay."
Conclusive analysis with carbon fibre electrodes
What else do the gland vesicles contain? This was analysed using carbon fibre electrodes in cooperation with Erwin Neher (Göttingen), winner of the Nobel Prize, who has a lot of experience with this technique. Together with Neher, the JMU researcher Sönke Scherzer adjusted the measurement method to the conditions prevailing inside the Venus flytrap.

The team positioned a carbon fibre electrode over the gland surface and waited with excitement what would happen. "At first, we were disappointed because we did not immediately detect signals as known from secretory cells in humans and animals," Scherzer recalls.

Should the vesicles contain hydrochloric acid in the first hours after catching the prey but no digestive enzymes yet? And no molecules yet that assure the enzymes' functioning in the acidic environment? Does the plant have to produce all this first?

That's exactly how it works: Molecular biologist Ines Fuchs found out that the plant only starts to produce the enzymes that decompose the prey after several hours. The first characteristic signals occurred after six hours and the process was in full swing 24 hours later. During this phase, the trap is completely acidic and rich in digestive enzymes.
Stabilising effect of glutathione keeps enzymes fit
Professor Heinz Rennenberg (Freiburg) also found glutathione (GSH) in the secreted enzyme. This molecule keeps the enzymes functional in the acidic environment of the Venus flytrap.

The same processes as described above take place in the same chronological order both when the sensory hairs are stimulated and when exposing the trap to the hormone jasmonate only. "A touch will very quickly trigger the jasmonate signalling pathway, but it takes time until the vesicles are produced and loaded with the proper freight which is facilitated by the hormone," Hedrich explains.
Calcium is a mandatory ingredient
How the Venus flytrap floods its "green stomach" with the right mixture and breaks down the prey into its nutrients can be visualised using magnetic resonance imaging. Eberhard Munz from the MRT centre of the JMU's Department of Physics was responsible for this task.

His experiments also showed that when the influx of calcium into the glands is blocked, the trap remains dry. "The calcium activation of the gland cells is therefore crucial," Hedrich says. "So we will now take a closer look at the biology of the calcium channels of Venus flytrap. We also want to investigate the mechanism which counts the signals transmitted by the sensory hairs in the gland and translates it into jasmonate-dependent biology."

Journal Reference:

Sönke Scherzer, Lana Shabala, Benjamin Hedrich, Jörg Fromm, Hubert Bauer, Eberhard Munz, Peter Jakob, Khaled A. S. Al-Rascheid, Ines Kreuzer, Dirk Becker, Monika Eiblmeier, Heinz Rennenberg, Sergey Shabala, Malcolm Bennett, Erwin Neher, Rainer Hedrich. Insect haptoelectrical stimulation of Venus flytrap triggers exocytosis in gland cells. Proceedings of the National Academy of Sciences, 2017; 201701860 DOI: 10.1073/pnas.1701860114

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genetics; molecular biology; biology; cell biology; wild animals; biochemistry research; epigenetics research; endangered plants

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Venus flytrap ( Dionaea muscipula) is a carnivorous plant. Catching its prey, mainly insects, with a trapping structure formed by its leaves, the plants' glands secrete an enzyme to decompose the prey and take up the nutrients released.

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“A natural weathering process called oxidation took place when air and water reacted with the copper plates.”

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“Over time the weathering of the copper created a thin layer of copper carbonate called a patina. “

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This image shows how erosion effects rocks.

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“Erosion is the general term that means the wearing down of landforms, including the toughest, tallest mountains.”

“Actually there are two forces that work together: weathering, which is the breakdown of land into smaller pieces, and erosion, which is the movement of the pieces removed by weathering.“

This supports the weathering and erosion of the Grand Canyon.

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Erosion is the general term that means the wearing down of landforms, including the toughest, tallest mountains. Actually there are two forces that work together: weathering, which is the breakdown of land into smaller pieces, and erosion, which is the movement of the pieces removed by weathering. Weathering is caused by wind, water, heat and cold; erosion happens via wind, water, and gravity. Weathering and erosion typically happen over hundreds, thousands, or even millions of years. Boulders become sand and mountains are reduced to smaller hills. The pieces move downhill, creating new landforms. It's a never-ending process.

Here is a very nice slide show about erosion you can share with your students:

www.nps.gov/tica/forteachers/upload/Erosion.pptx

It has a couple of good projects about how erosion happens. There are still more cool ideas here:

http://www.pinterest.com/mjkrech/teaching-weathering/

Glaciers, which are slow-moving hunks of ice, creep across the landscape as they melt and re-freeze. Along the way they pick up rocks and soil and carve the land they travel over. Glaciers shape valleys, ravines and lakes. Wind can blow hard enough to wear down rocks. With help from sand it picks up, wind can reshape a rocky landscape. It can also pull away topsoil and destroy fertile farmland. A good activity to demonstrate the power of wind erosion is to have students read about the Dust Bowl of the 1930s. Here are some activities that you might incorporate into your classroom:

http://www.pbs.org/kenburns/dustbowl/educators/whirlwind-activities/

Water is the primary cause of weathering (both chemical and mechanical) and erosion. Just a little drop of rain can carry away tiny bits of soil. So imagine what a brief downpour can do! Little streams join to become a bigger stream and the water rushes downhill. More and more sediment is picked up and carried along in streams and then into rivers. The faster the water rushes, the more the water wears away at the river banks, gathering more sediment and creating larger and larger valleys. It was moving water that created the Grand Canyon, which is about a mile (1,600 meters) deep and almost twenty miles wide (29 kilometers) in some parts. To note, it took about 5 million years to form.

Here's an activity to demonstrate the power of rain:

You'll need:

Play sand (amount depends on how many stations you want to set up)

Small pebbles

Dirt

2 large broiler or other shallow pans

Baster

Watering can

Water

Mop (just in case)

Mix up sand, dirt, pebbles with water to create a small landform on one end of your pan. You might let it dry overnight or just go for it. Set the pan at a slant with the 2nd pan positioned to catch the mess.

Use the baster to drop water on the landform, just a few drops at first. Then give it a nice shower with the watering can. Let students write down what happens with each step. Then for the climax, flood it.

Erosion is part of nature, but people can make erosion happen more quickly. Man-made structures such as housing developments, industry, oil drilling operations, dams, levees, floodgates and canals, and attempts to artificially build up land to house more people (New Orleans and Miami are good examples of this) have all caused our natural coastlines, riverbanks, wetlands and barrier islands to erode and often, completely disappear! All of these landforms normally help slow down flood peaks and sustain stream flows during droughts. Wetlands and barrier islands can even decelerate a storm surge from a hurricane. Our attempts to populate and alter the world's waterways and coastal areas, coupled with the rising sea levels (most scientists think due to climate change) have caused rapid and massive erosion around the world.

Streams and creeks are also at risk. In the 1960s, the U.S. Department of Fish and Wildlife decided that all the trees that had fallen into the rivers and streams were causing problems. So were the massive beaver dams that flooded the valleys and created huge wetlands. The trees formed logjams in the creek beds.. The beavers were flooding areas where people wanted to farm and provide pastureland for their domestic animals. All the debris and all the beaver dams... miles and miles of natural habitat that, historically and for thousands of years, and had provided a stable and healthy ecosystem, were removed.

This "clean up" pretty much turned all the native streams into fast-moving storm drains with eroded banks. A great percentage of wetlands were drained or diminished. The creeks, once filled with gravel beds, beaver dams, and natural logjams that provided nesting grounds and havens for native salmon and trout, were scoured down to nothing but bedrock and silt. In turn, in some species, the native fish populations were (and still are) decimated to the point of near-extinction..

Meanwhile the remaining population of North American beaver, estimated at about 10% of their original numbers by the turn of the 20th century because of trapping, were considered pests while in reality, these animals were part of an ecosystem that not only supported the native fish population, but provided habitat for other local animals and plants and helped provide clean water that filtered back into the streams, creeks, rivers, and eventually, the ocean.

Thankfully, in many areas, the clean-up practices have stopped. Watershed councils formed to try to help repair the eroded banks, and property owners with creek frontage are being educated about restoration efforts. Some of the things being done are:

1. Homeowners and volunteers are diligently planting native brush and trees along creek banks and eradicating invasive plant species that usurp native plants. Vegetation with a solid root system helps to keep the banks from further erosion while it provides shade for the creeks in the hot summer.

2. People with domestic livestock are being encouraged to keep their animals back from the creek and their manure picked up for other uses, such as organic fertilizer.

3. Projects to create fish habitat are gaining in popularity when volunteers and money are available. This involves adding "structures" which can consist of logs that are bolted to the creek bedrock so that they stay put. Then gravel can collect and other debris will build up while the water flow is slowed down, providing something closer to what nature intended in the first place.

4. Steep, eroded creek banks are being restored to be more gently sloping, sometimes by using rocks, fencing, or other structures to keep the banks from collapsing and eroding. Then native plants are reintroduced.

5. Logging practices have changed: timber companies can no longer cut trees close to creeks that host migratory fish populations. Shade is important to maintain a cool temperature in the creeks and streams. Meanwhile, trees falling into a creek are now seen as being healthy for the waterway!

Perhaps your students will want to volunteer to help with restoration efforts of our eroded creeks and streams. To locate local watershed groups in your state, go to:

To locate local watershed groups in your state, go to:
http://cfpub.epa.gov/surf/locate/index.cfm
Choose your state on the map

Under Environmental Information, click on Volunteer Monitoring Efforts

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Erosion! The Ever-changing Earth - Kids Discover

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Erosion is the general term that means the wearing down of landforms, including the toughest, tallest mountains. Actually there are two forces that work together: weathering, which is the breakdown of land into smaller pieces, and erosion, which is the movement of the pieces removed by weathering.

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According to the text,”The wood is chewed and mixed with saliva to make a paste which is used to construct the nest. She begins by creating a centre stalk called a petiole which she covers in a chemical that repels ants. “

This explains how this is a chemical change and how the queen bees saliva and the wood chewed is used to construct the nest and the queen bee digests some wood with her saliva.

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Wow

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Time Lapse of Paper Wasps Building a Nest  --  by Bill Klipp www.WildlifePhotos.me

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“Effel’s design allows the Statue of Liberty to move with the changes in temperature and wind speed.”

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Our is chemical change because the text states “it secretes digestive enzymes. These break down the trapped insect.”

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There is 3 parts of the insect Foregut is the mouth part of the insect and where they store food. Midgut is the digestion part, where it breaks down, to transport it to the hind gut. The hind gut is the thread part that moves around a lot to help break it down.

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7. Insect digestive and excretory systems

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“With a mouthful of wood fibers, the queen uses the saliva in her mouth to break down the wood fibers until they form a soft paper pulp.”

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“As the Colorado River did its work, slowly eroding layer after layer of rock, the Earths tectonic plates in the area shifted to push the areas on each side of the river to higher elevations.”

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Wasps make “paper” with there saliva
“They actually make there own building materials by turning raw wood into paper pulp”this is a chemical change

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This article explains how erosion affected the Grand Canyon.

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Erosion is the general term that means the wearing down of landforms, including the toughest, tallest mountains. Actually there are two forces that work together: weathering, which is the breakdown of land into smaller pieces, and erosion, which is the movement of the pieces removed by weathering. Weathering is caused by wind, water, heat and cold; erosion happens via wind, water, and gravity. Weathering and erosion typically happen over hundreds, thousands, or even millions of years. Boulders become sand and mountains are reduced to smaller hills. The pieces move downhill, creating new landforms. It's a never-ending process.

Here is a very nice slide show about erosion you can share with your students:

www.nps.gov/tica/forteachers/upload/Erosion.pptx

It has a couple of good projects about how erosion happens. There are still more cool ideas here:

http://www.pinterest.com/mjkrech/teaching-weathering/

Glaciers, which are slow-moving hunks of ice, creep across the landscape as they melt and re-freeze. Along the way they pick up rocks and soil and carve the land they travel over. Glaciers shape valleys, ravines and lakes. Wind can blow hard enough to wear down rocks. With help from sand it picks up, wind can reshape a rocky landscape. It can also pull away topsoil and destroy fertile farmland. A good activity to demonstrate the power of wind erosion is to have students read about the Dust Bowl of the 1930s. Here are some activities that you might incorporate into your classroom:

http://www.pbs.org/kenburns/dustbowl/educators/whirlwind-activities/

Water is the primary cause of weathering (both chemical and mechanical) and erosion. Just a little drop of rain can carry away tiny bits of soil. So imagine what a brief downpour can do! Little streams join to become a bigger stream and the water rushes downhill. More and more sediment is picked up and carried along in streams and then into rivers. The faster the water rushes, the more the water wears away at the river banks, gathering more sediment and creating larger and larger valleys. It was moving water that created the Grand Canyon, which is about a mile (1,600 meters) deep and almost twenty miles wide (29 kilometers) in some parts. To note, it took about 5 million years to form.

Here's an activity to demonstrate the power of rain:

You'll need:

Play sand (amount depends on how many stations you want to set up)

Small pebbles

Dirt

2 large broiler or other shallow pans

Baster

Watering can

Water

Mop (just in case)

Mix up sand, dirt, pebbles with water to create a small landform on one end of your pan. You might let it dry overnight or just go for it. Set the pan at a slant with the 2nd pan positioned to catch the mess.

Use the baster to drop water on the landform, just a few drops at first. Then give it a nice shower with the watering can. Let students write down what happens with each step. Then for the climax, flood it.

Erosion is part of nature, but people can make erosion happen more quickly. Man-made structures such as housing developments, industry, oil drilling operations, dams, levees, floodgates and canals, and attempts to artificially build up land to house more people (New Orleans and Miami are good examples of this) have all caused our natural coastlines, riverbanks, wetlands and barrier islands to erode and often, completely disappear! All of these landforms normally help slow down flood peaks and sustain stream flows during droughts. Wetlands and barrier islands can even decelerate a storm surge from a hurricane. Our attempts to populate and alter the world's waterways and coastal areas, coupled with the rising sea levels (most scientists think due to climate change) have caused rapid and massive erosion around the world.

Streams and creeks are also at risk. In the 1960s, the U.S. Department of Fish and Wildlife decided that all the trees that had fallen into the rivers and streams were causing problems. So were the massive beaver dams that flooded the valleys and created huge wetlands. The trees formed logjams in the creek beds.. The beavers were flooding areas where people wanted to farm and provide pastureland for their domestic animals. All the debris and all the beaver dams... miles and miles of natural habitat that, historically and for thousands of years, and had provided a stable and healthy ecosystem, were removed.

This "clean up" pretty much turned all the native streams into fast-moving storm drains with eroded banks. A great percentage of wetlands were drained or diminished. The creeks, once filled with gravel beds, beaver dams, and natural logjams that provided nesting grounds and havens for native salmon and trout, were scoured down to nothing but bedrock and silt. In turn, in some species, the native fish populations were (and still are) decimated to the point of near-extinction..

Meanwhile the remaining population of North American beaver, estimated at about 10% of their original numbers by the turn of the 20th century because of trapping, were considered pests while in reality, these animals were part of an ecosystem that not only supported the native fish population, but provided habitat for other local animals and plants and helped provide clean water that filtered back into the streams, creeks, rivers, and eventually, the ocean.

Thankfully, in many areas, the clean-up practices have stopped. Watershed councils formed to try to help repair the eroded banks, and property owners with creek frontage are being educated about restoration efforts. Some of the things being done are:

1. Homeowners and volunteers are diligently planting native brush and trees along creek banks and eradicating invasive plant species that usurp native plants. Vegetation with a solid root system helps to keep the banks from further erosion while it provides shade for the creeks in the hot summer.

2. People with domestic livestock are being encouraged to keep their animals back from the creek and their manure picked up for other uses, such as organic fertilizer.

3. Projects to create fish habitat are gaining in popularity when volunteers and money are available. This involves adding "structures" which can consist of logs that are bolted to the creek bedrock so that they stay put. Then gravel can collect and other debris will build up while the water flow is slowed down, providing something closer to what nature intended in the first place.

4. Steep, eroded creek banks are being restored to be more gently sloping, sometimes by using rocks, fencing, or other structures to keep the banks from collapsing and eroding. Then native plants are reintroduced.

5. Logging practices have changed: timber companies can no longer cut trees close to creeks that host migratory fish populations. Shade is important to maintain a cool temperature in the creeks and streams. Meanwhile, trees falling into a creek are now seen as being healthy for the waterway!

Perhaps your students will want to volunteer to help with restoration efforts of our eroded creeks and streams. To locate local watershed groups in your state, go to:

To locate local watershed groups in your state, go to:
http://cfpub.epa.gov/surf/locate/index.cfm
Choose your state on the map

Under Environmental Information, click on Volunteer Monitoring Efforts

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Erosion! The Ever-changing Earth - Kids Discover

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Erosion is the general term that means the wearing down of landforms, including the toughest, tallest mountains. Actually there are two forces that work together: weathering, which is the breakdown of land into smaller pieces, and erosion, which is the movement of the pieces removed by weathering.

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This video shows that weathering and erosion breaks down rocks.

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Weathering and Erosion: Crash Course Kids #10.2

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“Did you know that a river can carve out a deep ravine between cliffs over the course of a million years?”