Term | Definition |
air | The mixture of gases found in Earth’s atmosphere. Dry air is primarily nitrogen (N2 |
altitude | The elevation above sea level. |
atmosphere | The gases that surround a planet or moon. On Earth, the air. |
climate | The average weather for a place over a long period of time (usually at least 30 years). |
clouds | A visible collection of water droplets in the atmosphere. Clouds usually form hundreds of meters above Earth’s surface but fog is a cloud formed near Earth’s surface. |
condensation | The process of change in state from gas to liquid, or the droplets of liquid formed from this process. |
energy | The ability to cause motion. Energy comes in many forms and is measured in joules. |
evaporation | The process of change in state from a liquid to a gas. |
freezing | To change from a liquid to a solid state. |
front (cold, warm) | A boundary where a mass of air meets another air mass of a different temperature. |
Gulf Stream | A strong ocean current that flows on the surface of the Atlantic Ocean from the Gulf of Mexico to northwestern Europe. |
humidity | The amount of water vapor in the air. |
latitude | The distance in degrees of a location north or south of the equator |
melting | To change from a solid to liquid state. |
ocean current | Regular movements of large amounts of water in the ocean. |
precipitation | The movement of water, in solid or liquid form, from the atmosphere back to the surface of the earth. Rain, snow, sleet, and hail are examples. |
pressure (high, low) | A force applied to a surface. It is measured in a force unit per area, such as psi (pounds per square inch) or millibars (100 newtons per square meter). |
prevailing wind | The most common wind direction for a region. On the earth, the direction of the prevailing winds are related to the latitude of the region. |
troposphere | The lowest layer of the earth’s atmosphere, where people live and most weather occurs. |
water cycle | The movement of water from one state to another as it circulates through the earth’s crust, oceans, and atmosphere. Water evaporates from the surface, rises and cools at higher elevations, condenses as rain or snow, and falls to the surface where it colle |
water vapor | Water in a gaseous state. |
weather | The condition of the atmosphere, including temperature, precipitation, and cloud cover, at a particular time and place. |