Dust and clouds within me reflect some sunlight back into space.
I trap infrared radiation coming from Earth. What am I?
The Sun's rays constantly pour down over Earth like a solar shower. Some of the radiation penetrates the atmosphere; some is reflected back into space by the dust and clouds in the lower atmosphere. The energy that reaches Earth's surface may be reflected by snow, ice, water, or sand. If it strikes land, the energy is absorbed by Earth, producing heat, or infrared radiation. The reflected energy and these long infrared waves emitted by Earth are trapped by certain gases in the atmosphere, such as water vapor, carbon dioxide, some CFCs, methane, nitrous oxide, and tropospheric ozone. (This is "bad" ozone, as opposed to the "good" ozone that blocks UV rays in the stratosphere.) Because the infrared radiation is trapped, the surface temperature of Earth rises; this is called the "greenhouse effect." Because burning of fossil fuels is increasing the concentration of these gases in the atmosphere, Earth's temperature may go from pleasantly warm to unpleasantly hot.
Using the information provided above and the word bank below, label the blanks in the illustration.
| outgoing infrared radiation | clouds | incoming solar radiation |
| Earth's surface | fossil fuel burning |
Reference: "Earth's Mysterious Atmosphere - ATLAS 1 Teacher's Guide with Activities" (For use with Middle-School students.) NASA EP-282/11-91, pp.44.