| A | B |
|---|
| atmosphere | a mixture of gases that surrounds Earth |
| air pressure | the measure of the force with which air molecules push on a surface |
| troposphere | the lowest layer of the atmosphere, in which temperature decreases at a constant rate as altitude increases |
| stratosphere | the layer of the atmosphere that is above the troposphere and in which temperature increases as altitude increases |
| mesosphere | the layer of the atmoshpere between the stratosphere and the thermosphere and in which temperature decreases as altitude increases |
| thermosphere | the uppermost layer of the atmosphere, in which temperature increases as altitude increases |
| auroras | charged particles found in the ionosphere, also known as northern or southern lights |
| ozone layer | located in the stratosphere, it protects life on Earth by absorbing harmful ultraviolet radiation |
| radiation | the transfer of energy as electromagnetic waves |
| thermal conduction | the transfer of energy as heat through a material |
| convection | the transfer of thermal energy by the circulation or movement of a liquid or gas |
| convection current | a cycle of warm air rising and cool air sinking causing a circular movement of air |
| greenhouse effect | the warming of the surface and lower atmosphere of Earth that occurs when water vapor, carbon dioxide, and other gases absorb and reradiate thermal energy |
| global warming | a gradual increase in average global temperature |
| radiation | The transfer of energy as electromagnetic waves. It can transfer energy between objects that are not touching each other. |
| infrared radiation | Most of the warmth that comes from the sun is infrared. |
| convection current | Thermal expansion causes warmer substances to become less dense which is forced up by surrounding, colder matter that is more dense and sinking. Hot matter rises, cools and then becomes more dense and sinks. |
| conduction | Transfer of energy from one object to another through direct contact. Faster moving particles of the warmer substance transfer energy to the slower moving particles in the cooler object. |
| What percentage of the atmosphere is nitrogen? | 78% |
| What percentage of the atmosphere is oxygen? | 21% |
| Why is air pressure greatest at Earth's surface? | Gas molecules are being pulled down toward the surface by gravity |
| What causes differences in air temperature at different altitudes? | air temperature changes as altitude increases because of gases absorbing solar energy |
| What happens to most solar energy that reaches Earth's atmosphere? | it is absorbed by Earth's surface |
| How does the atmosphere help protect life on Earth? | 1. It surrounds and protects Earth 2. Provides the air we breathe 3. Protects Earth from harmful solar radiation and from space debris 4. Controls the temperature on Earth |
| Which atmospheric layers are auroras found? | Thermosphere (ionosphere) |
| What are the effect of ozone depletion? | It allows more UV rays to reach Earth's surface |
| How does global warming occur? | It may occur due to an increase in greenhouse gases |
| How does the greenhouse effect keep the Earth warm? | The gases in the atmosphere absorb thermal energy and radiate it back to the Earth. |
