1. Weather
SOL 4.6

2. atmosphere
the layer of air that surrounds our planet

3. air pressure
particles of air pressing down on the Earth’s surface

4. troposphere
the layer of the Earth’s atmosphere closest to Earth

5. stratosphere
the layer of the Earth’s atmosphere containing most of the atmosphere’s ozone

6. greenhouse effect
the warming of earth caused by the atmosphere trapping thermal energy from the sun

7. air mass
a huge body of air which all has similar temperature and moisture

8. front
the border where two air masses meet

9. cirrus
wispy, high altitude clouds that are made up of ice crystals

10. cumulus
puffy cotton-ball clouds that begin to form when water droplets condense at the middle altitudes

11. cumulonimbus
towering, dark rain clouds with nimbus, or halo, of gray-white

12. stratus
dark gray clouds that form a low layer and sometimes bring light rain or snow
shower

13. barometer
measures air pressure

14. humidity
amount of water vapor in the air

15. hygrometer
Instrument that measures humidity