| A | B |
|---|
| air | a mixture of gases that surrounds the Earth and consists mainly of the gases nitrogen and oxygen |
| nitrogen | a gas in the air used by plants for growth; it makes up the most plentiful gas in the air |
| oxygen | a gas in the air essential to life |
| carbon dioxide | a gas in the air use by plants to make food |
| water vapor | water that is in the form of a gas |
| atmosphere | the blanket of air that surrounds the Earth and is made of gases, liquids, and some solid matter |
| troposphere | the layer of the atmosphere closest to the surface of the Earth in which the weather occurs |
| weather | the condition of the atmosphere at a certain place and time |
| greenhouse effect | the process by which heat from the sun builds up near the Earth's surface and is trapped by the atmosphere |
| wind | the movement of air over the Earth's surface |
| matter | what air is made up of |
| space | air takes up ... |
| weight | air has ... |
| upward | heating the air below a paper bag causes the bag to move ... |
| farther apart | particles in warm air are _____ than particles in cool air |
| heat | to make a hot air balloon rise, one should _____the air? |
| sinks | when air cools, it ... |
| mass | another word for how much something weighs |
| land | air over this heats up faster than air over water |
| water | Air over land heats up faster, than air over ..... |
| winds | caused by the uneven heating of the air |
| sea breeze | occurs when cooler air from over the water takes the place of warmer air over the land |
| greater | a balloon's weight would be _______ after you blow it up, because you added air, and air has weight. |
