Chapter 7.1 to 7.5 Test Study Guide Answer Key
1. List at least three reasons that the atmosphere is important to living things.
Make conditions on Earth suitable for living things: containing oxygen and other gases that living things need to survive, trapping energy from the sun to keep Earth warm, protecting living things from UV radiation, preventing Earth’s surface from being hit by most meteoroids.
2. Give at least one important characteristic of each of the four main layers of the atmosphere.
Troposphere - Weather occurs here
Stratosphere – Contains ozone
Mesosphere – Protects us from meteoroids
Thermosphere – Temperatures are extremely high
3. In what form does energy from the sun travel to Earth?
Most of the energy from the sun travels to Earth in the form of visible light.
4. How does ozone protects us in the stratosphere?
Ozone in the stratosphere absorbs UV radiation from the sun.
5. How can density be determined? Density = Mass / Volume
6. How does altitude affect the quantity of oxygen molecules? Does the air composition stay the same at high altitude?
There are fewer oxygen molecules at high altitudes because the air is less dense at a high altitude. However, the air still contains 21 percent oxygen at any altitude.
7. As altitude increases, how does air pressure change? How does density change?
As altitude increases, the air pressure decreases and the density also decreases.
8. What instruments can be used to measure air pressure?
The instruments that can measure air pressure are Mercury barometers and aneroid barometers.
9. Scientists classify the four layers of the atmosphere according to changes in ___temperature______.
10. What causes smog and acid rain? They are caused by burning fossil fuels.
11. What’s the difference between greenhouse effect and scattering?
Greenhouse effect is caused by gases in the atmosphere holding heat that is radiated from Earth’s surface.
Scattering happens when dust particles and gases in the atmosphere reflect light in all directions.
12. What is the composition of Earth’s atmosphere?
78% nitrogen, 21% oxygen, and 1% other gases
13. Give an example of each type of heat transfer.
radiation – warmth from a fire; feeling the warmth without touching the object
conduction – Walking barefoot on hot sand ( direct transfer of heat)
convection – Heating soup in a pot ( in liquids and gases)
14. How is heat transferred in the troposphere?
Heat is transferred in the troposphere mostly by convection.