| A | B |
|---|
| Weather | Condition of Earth's atmosphere |
| Atmosphere | layer of gases that surrounds Earth |
| Ozone | form of oxygen three atoms |
| pollutant | harmful substance in the air |
| smog | smoke and fog |
| acid rain | rain that contains more acid than normal |
| Density | amount of mass in a given volume |
| Air pressure | the force of a column of air pushing |
| barometer | measures changes in air pressure |
| Altitude | elevation above sea level |
| Troposphere | lowest layer of Earth's atmosphere |
| Statosphere | second lowest layer of atmosphere |
| ozone layer | upper part of the stratosphere |
| mesophere | the middle layer of Earth's atmosphere |
| thermosphere | outermost layer of Earth's atmosphere |
| ionosphere | lower part of the thermoshpere |
| ion | electrically charge particles |
| aurora borealis | colorful glowing display in the sky |
| exophere | the outer layer of the thermosphere extending into space |
| layer that absorbs radiation | ozone layer |
| layer where weather happens | troposhere |
| layer where meteors burn up | mesosphere |
| layer 80 km above the Earth | thermosphere |
| layer that reflects back radio waves | ionosphere |
| layer where satellites are | exosphere |
| radiant energy | energy from the sun |
| fossil fuel | any fuel made from coal |
| what less dense things do | float |
| pushes in all directions | air pressure |
| natural source of pollution | ocean waves, forest fires, volcanoes |
| artificial source of pollution | factories, cars, burning fossil fuels |
| compositon of air | carbon dioxide, oxygen, methane, nitrogen, trace gases |
| trace gas | small amount of gas in the atmosphere |
| 21% | oxygen in the air |
