| A | B |
|---|
| weather | the atmospheric conditions at a particular time |
| atmosphere | the envelope of gases surrounding the Earth |
| oxygen | 21% of the air; we need it to breathe |
| nitrogen | 78% of the air |
| troposphere | the layer of the atmosphere closest to the surface where weather occurs. |
| stratosphere | the layer of the atmosphere above the troposphere. A layer of ozone here protects us from radiation from the sun |
| mesosphere | the layer of the atmosphere that burns up millions of meteors every day |
| ionosphere | this layer of the atmosphere has charged particles. The aurora borealis is here. Radio waves bounce back from here. |
| exosphere | the outermost layer of the atmosphere; satellites orbit here |
| aurora borealis | also known as the northern lights, these colored lights are made of charged aprticles. |
| jet stream | a strong wind located at the bottom of the stratosphere. |
| water vapor | water in a gas state; there is a lot of it in the troposphere. |
| ultraviolet radiation | electromagnetic waves that come from the sun to the EArth |
| sun | the star at the center of our solar system; its heat and light allow life to exist on Earth |
