Across
- 3. When volume increases, air molecules __________.
- 5. anything that has mass and takes up space.
- 7. an instrument used to measure air pressure.
- 8. the amount of matter in an object or sample.
- 9. When volume decreases, air molecules __________.
- 10. a gas that makes up about 21% of earth's atmosphere.
- 12. the amount of mass in a sample of matter compared to its volume.
- 13. an instrument that measures thermal energy as temperature.
Down
- 1. a space containing no matter, not even air.
- 2. air pressure at ______ _______ is higher than it is at the top of a mountain.
- 4. air pressure ___________ as elevation increases.
- 6. the layer of gases around the earth.
- 11. prevents gravity from attracting air particles to the ground.