Unit 4: Section B Summary: 1-8

1.    The higher the frequency of electromagnetic radiation, the more energy it contains.

2.    The word “spectrum is a good descriptor because it is defined as a broad sequence of related quantities.

3.    Visible light assists photosynthesis because it can energize electrons in some chemical bonds. Infrared radiation does not contain enough energy, and ultraviolet is too harmful.

4.    Electromagnetic Radiation:

a.    Infrared radiation, visible light, and ultraviolet radiation.

b.    Infrared is basically heat energy and affects the temperatures of nonliving and living things, including Earth. Visible radiation powers plant photosynthesis, which releases oxygen into the atmosphere. Ultraviolet, in its one of its most energetic states, is linked to skin cancer, but the vitamin-D it provides is necessary for human health.

5.    Visible radiation does not provide enough energy to be able to sterilize lab goggles. Ultraviolet light, on the other hand, has photon with enough energy to break covalent bonds (in its UV-C form) therefore killing and destroying bacteria and viruses.

6.    Infrared radiation is mostly absorbed by carbon dioxide and water vapor in the atmosphere and does not reach the Earth’s surface, however, some its higher energy waves are absorbed by the earth and re-radiated as infrared energy. 90% of the visible radiation emitted from the sun reaches the earth and is scattered by water, air, and dust, casing the red sunsets and blue skies. Ultraviolet radiation in general does not reach the earth’s surface. UV-C is completely absorbed by the stratosphere, and most UV-B and UV-A radiation is absorbed by the ozone layer as well.

7.    Solar radiation that reaches Earth’s surface increases its temperature after being trapped by greenhouse gases such as carbon dioxide, methane, and nitrous oxide. Another affect is the increase of water vapor. The more radiation, the hotter it gets causing more water to evaporate and enter the atmosphere.

8.    Heat capacity:

a.    A lake will heat up more easily than asphalt because it can store more heat.

b.    The cause of this is because water has a high specific heat capacity than asphalt and other land materials.