2. Weather & Climate

3. air pressure the weight of air

4. humidity a measure of the amount of water in the air

5. precipitation any form of water that falls from clouds, such as rain or snow

6. evaporation the process by which liquid changes into a gas

7. condensation the process by which a gas changes back into a liquid

8. air mass a large body of air that has nearly the same temperature and humidity throughout

9. front the boundary between air masses

10. climate the average of all weather conditions through all seasons over a period of time

11. microclimate the climate of a very small area

12. El Niño a short-term climate change that occurs every two to ten years

13. greenhouse effect process by which the Earth’s atmosphere absorbs heat

14. global warming the hypothesized rise in Earth’s average temperature from excess carbon dioxide