| A | B |
|---|
| air pressure | the weight of air pressing on the earth's surface |
| matter | anything that has mass and takes up space |
| mass | the amount of matter in an object |
| balance pan | used to measure mass |
| spring scale | measures weight |
| barometer | measures air pressure |
| gravity | the earth's pull on all matter |
| rain gauge | measures the amount of precipitation |
| grams | units in which mass is measured with the balance pan |
| newtons | units in which weight is measured with the spring scale |
| rising barometer | predicts fair weather |
| fallling barometer | predicts precipitation |
| air pollution | harmful gases or particles in the air |
| soot | very black pollution caused by burning |
| oxygen | part of air people and animals need |
| altimeter | measures altitude (for airplanes) |
| acid rain | rain containing harmful pollutants |
| ozone | an air pollutant harmful for us to breathe |
