Figure 15.13: An image of a dog taken by an infrared sensor. The image shows the different
amounts of heat radiating from the dog. ( 19 )
removes UVC, most UVB and some UVA from incoming sunlight. O 2 , CO 2 and H 2 O also
filter out other wavelengths from solar energy.
Figure 15.14: In the atmosphere, gases filter some wavelengths from incoming solar energy.
The yellow field shows the wavelengths of energy that reach the top of the atmosphere. The
red field shows the wavelengths that reach sea level. The amount of radiation is reduced
overall as different gases filter out different wavelengths. Ozone filters out the shortest
wavelength ultraviolet and oxygen filters out most infrared, at about 750 nm. ( 15 )
Different parts of the Earth receive different amounts of solar radiation. This is because the
Sun’s rays strike the Earth’s surface most directly at the equator. As you move away from
the equator, you will notice that different areas also receive different amounts of sunlight in