| A | B |
|---|
| Air | the mixture of gases that make up Earth’s atmosphere |
| Altitude | a measure of the distance of an object is about sea level; usually that object is airborne |
| Atmospheric pressure | a measure of the force per unit area of air molecules in the atmosphere at a given altitude |
| Barometer | an instrument that measures atmospheric pressure |
| 78% | amount of Nitrogen in the atmosphere |
| 21% | amount of Oxygen in the atmosphere |
| Air molecules | what our atmosphere consists of |
| 5 | number of layers in the atmosphere |
| Troposphere | a layer of the atmosphere that occurs from 0 to about 11 kilometers about Earth’s surface; all weather occurs here |
| Stratosphere | a layer of the atmosphere that occurs from about 11 kilometers to 50 kilometers about Earth’s surface; location of the ozone layer |
| Mesosphere | a layer of the atmosphere that occurs from about 50 kilometers to 80 kilometers above Earth’s surface; the coldest layer |
| Thermosphere | a layer of the atmosphere that occurs from about 80 kilometers to about 500 kilometers; this layer has a low density of air molecules and a very high temperature |
| Exosphere | the region of the atmosphere that begins at about 500 kilometers above Earth and extends into space; the location of the orbits of satellites |
| Ionosphere | portions of the atmosphere in the region of the thermosphere where electricity can be transmitted |
| Specific heat | the amount of energy needed to raise the temperature of 1 gram of a substance by 1 degree Celsius |
| Rotation | the motion of Earth spinning on its axis; one rotation is called a day |
| Revolution | the motion of Earth moving around the sun; one revolution is called a year |
| 4 | the number of seasons on Earth |
