| A | B |
|---|
| radiation | the transfer of energy as electromagnetic waves |
| two billionths | amount of the sun’s energy received by the Earth |
| absorbed | 70% of the sun’s energy is ____________. |
| reflected | 30% of the sun’s energy is ____________. |
| conduction | the transfer of heat from one material to another by direct physical contact |
| convection | the transfer of heat by the circulation or movement of a liquid or a gas |
| sinks | During convection, cold air or liquid ______. |
| rises | During convection, hot air or liquid ______. |
| convection current | the circular movement of air in a continual process of warm air rising and cool air sinking |
| greenhouse effect | the natural heating process of Earth by which some gases in the atmosphere trap thermal energy |
| global warming | a rise in average global temperatures |
| radiation balance | the balance between incoming energy and outgoing heat |
| warming | Global __________ could cause major changes in plant and animal communities. |
