EARTH & SUN #2

layer of gases surrounding Earth

• atmosphere
• asteroid
• cloud
• crater

about 78% of Earth's atmosphere

• air
• nitrogen
• oxygen
• helium

about 21% of Earth's atmosphere

• air
• nitrogen
• oxygen
• helium

gas that protects life on Earth by absorbing dangerous ultraviolet light from the Sun

• air
• nitrogen
• oxygen
• ozone

process by which liquid water changes into water vapor

• evaporation
• condensation
• precipitation
• gravitation

process by which water vapor changes into liquid water

• evaporation
• condensation
• precipitation
• gravitation

rain, snow, sleet or hail that falls from clouds

• evaporation
• condensation
• precipitation
• gravitation

region of the atmosphere that begins at Earth's surface and extends upward to 20 km

• stratosphere
• thermosphere
• mesosphere
• troposphere

scientist who studies the weather

• geologist
• astronomer
• biologist
• meteorologist

instrument to measure temperature

• thermometer
• barometer
• hygrometer
• wind vane