| A | B |
|---|
| solid | a state of matter that has a definite (fixed) volume and shape |
| liquid | a state of matter that has a definite (fixed) volume and takes on the shape of its container |
| gas | a state of matter that has no definite (fixed) volume or shape |
| mixture | a combination of different substances that retain their original properties and can be separated |
| physical change | a change in the physical property of a substance, not the substance itself such as tearing paper |
| density | a measure of the amount of mass in a given volume of a substance (D = m/v) |
| cycle | a series of events or actions that repeat themselves regularly (ex: the water cycle) |
| atmosphere | the layer of air that surrounds the earth that supports and protects life |
| troposphere | the layer of the atmosphere that is nearest to Earth's surface |
| stratosphere | the layer of the atmosphere which includes ozone |
| ozone layer | a part of the atmosphere that protects life on Earth by absorbing harmful ultraviolet radiation from the Sun |
| greenhouse effect | a process where certain gases in a planet's atmosphere absorb radiation resulting in an increase in surface temperature |
| air pressure | the force of air molecules pushing on an area |
| barometer | an instrument used to measure air pressure in the atmosphere |
| weather | the condition of the Earth's atmosphere at a particular time and place |
| evaporation | the process by which liquid changes into gas |
| condensation | the process by which gas changes into a liquid |
| precipitation | any type of liquid or solid water that falls to Earth's surface, such as rain, sleet, snow, or hail |
| cirrus | clouds that form in very high altitudes, made of ice crystals, and have a wispy or feathery appearance |
| cumulus | clouds that are puffy and white usually with darker bases, the tallest of these (cumulonimbus) produce thunderstorms |
| stratus | clouds that are smooth and form in flat layers, the low ones can block the Sun and create long periods of precipitation |
| front | the boundary between two air masses, there are 4 types: warm, cold, stationary, and occluded |
| high pressure | a generally calm and clear weather system |
| low pressure | a large and often stormy weather system that often forms where air masses meet |
| air mass | a large volume of air that has nearly the same temperature and humidity at different locations in the same altitude |
| climate | the characteristic of weather conditions in an area over a long period of time |
| ocean current | a stream of water that flows through out the ocean in a regular pattern |
