Homework 7/21/13

1. The frequency of electromagnetic radiation/photons and energy are directly proportional because the wavelength of electromagnetic radiation/photons and energy are inversely proportional.


2. Spectrum is a good descriptor of the types of energy found in electromagnetic radiation because the spectrum shows the range of energy from high to low. 


3. Visible light is useful in plant photosynthesis because visible radiation can energize electrons in some chemical bonds which provides energy needed for photosynthesis reactions. 


4. 
a. Infrared, visible, ultraviolet
b. Infrared radiation is essentially heat energy, which warms living things. Visible radiation can energize electrons in chemical bonds. Although ultraviolet radiation can cause sunburns, skin cancer, and can kill bacteria and destroy viruses, it is necessary for humans in some amounts, for exposure to it results in the production of vitamin D. 



5. UV-C photons have enough energy to break covalent bonds, and therefore, lead to chemical changes in the materials exposed to radiation; UV-C radiation can kill bacteria and destroy viruses, as it can damage other living organisms. 


6. Two natural major greenhouse gases, carbon dioxide and water vapor, absorb infrared radiation and reradiate the energy back to earth. On a clear day, 90% of visible radiation directed towards earth travels to Earth's surface. UV-C radiation is absorbed in the stratosphere before reaching earth's surface and most UV-A and UV-B radiation us absorbed by the stratospheric ozone layer (and does not reach the earth's surface).


7. When more greenhouse gases are produced, such as carbon dioxide and water vapor, more infrared radiation is absorbed. This results in more energy reradiated on earth's surface, hotter water affecting the hydrologic cycle (more water vapor produced), and an overall hotter earth. 


8. 
a. An asphalt, such as snow, sand, or concrete, warms up more quickly when exposed to sunlight. This is because when solar radiation strikes these materials, it is reflected and illuminated back into space. On the other hand, lake water does reflect light, but also stores absorbs and stores heat. 
b. Water, in forms like water vapor, act as greenhouse gases and absorb infrared light and reradiate it back to earth's surface. Asphalts directly reflect light sources back into space.


14. This infrared radiation is not directly from the sun, but is the product of transformed UV and visible radiation from the sun within the clouds. Infrared radiation is essentially heat energy, that these greenhouse gases have made from trapping UV and visible light in order to absorb, reradiate, and reflect the heat energy onto earth's surface. 

15. 
a. 
Natural: 1. breathing; 2. bacterial decay.
Human: 1. agricultural and industrial activities; 2. burning of fossil fuels.
b.
Natural: 1. decomposition of plants; 2. decomposition of animal wastes
Human: 1. Refining fossil fuels; 2. raising of livestock.

16. 

a. lower altitude, increase in greenhouse/atmospheric gases, higher air pressure. 
b. higher altitude, decrease in greenhouse/atmospheric gases, lower air pressure.

17. What goes on in greenhouse with transparent glass imitates the way the greenhouse gases transform UV and visible radiation to IR radiation within clouds, and reradiate and reflect the heat energy within earth, or the greenhouse (since the infrared light cannot escape through the glass, like earth's CO2 and H2O gas that act as a shield). This is why on a sunny winter day, a greenhouse with transparent glass walls is much warmer than is a structure with opaque wooden walls. 

18. 

19. Three chemical reservoirs of carbon atoms include atmospheric CO2 gas, solid calcium carbonate (CaCO3) in limestone, and organic molecules. 

20. Carbon naturally moves within Earth's systems. The carbon atom could be part of the atmosphere as a gas as a result of photosynthesis, in the lithosphere as plant or animal waste decay, or part of the hydrosphere as limestone.