4SBS, #1-8, page 360

1) Write an equation or a sentence that describes the relationship between the frequency of electromagnetic radiation and its energy.

The frequency of electromagnetic radiation/photons and energy are directly proportional, where as wavelength of electromagnetic radiation/photons and energy are inversely proportional.

2) Why is the word spectrum a good descriptor of the types of energy found in electromagnetic radiation?

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

3) Why is visible light useful in plant photosynthesis, while other forms of electromagnetic radiation are not?

Visible light is useful in plant photosynthesis while other forms of electromagnetic radiation are not because visible radiation can energize electrons in some chemical bonds-- providing energy needed for photosynthesis reactions.

4)
a. List the main types of electromagnetic radiation in order of increasing energy.
b. Describe how each radiation listed in your answer to Question 4a affects living things.

a. Infrared, visible, ultraviolet
b. Infrared radiation is essentially heat energy, which warms living things. Visible radiation can energize electrons in chemical bonds, an example being photosynthesis. 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) Ultraviolet light is often used to sterilize chemistry laboratory protective goggles. Why is ultraviolet light effective for this use, while visible light is not effective?

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) Compare infared, visible, and ultraviolet radiation in terms of how well they are absorbed by the atmosphere.

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) Describe the two main effects of the solar radiation that reaches Earth's surface.

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. Compare lake water and asphalt in terms of how readily each warms up when exposed to sunlight.
b. What properties of these two materials account for the differences in their behavior?

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.