| A | B |
|---|
| air mass | a huge body of air that has similar temperature and humidity throughout |
| air pressure | the weight of air around Earth pressing down on Earth's surface |
| anemometer | a weather instrument used to measure wind speed |
| atmosphere | the blanket of air that surrounds Earth |
| barometer | a weather instrument used to measure air pressure |
| cirrus cloud | a high-altitude, wispy cloud composed of ice crystals |
| climate | the average weather pattern in an area over a long period of time |
| cold front | the boundary where a cold air mass meets and moves under a warm air mass |
| condensation | the process by which a gas changes to a liquid |
| cumulus cloud | a puffy cloud that appears to rise from a flat bottom |
| evaporation | the process by which a liquid changes to a gas |
| front | a boundary between two air masses of different temperatures |
| humidity | a measure of the amount of moisture in the air |
| hurricane | a huge, powerful, swirling storm with heavy rain and strong winds of 119 km (74 miles) per hour or higher |
| precipitation | water falling from the atmosphere to Earth as part of the water cycle, usually in the form of rain, sleet, hail, or snow |
| stratus cloud | a low, flat, layered cloud |
| temperature | a measure of how hot or cold something is |
| thermometer | a weather instrument used to measure temperature |
| tornado | a rapidly spinning funnel of air that extends from the bottom of a thundercloud to the ground |
| troposphere | the layer of the atmosphere closest to Earth's surface, where most weather occurs |
| warm front | the boundary where a warm air mass meets and slides over a cold air mass |
| water cycle | the movement of water from Earth's surface to the atmosphere and back again |
| weather | the condition of the atmosphere at a certain place and time |
| convection | movement of energy through the troposphere by means of rising and sinking of air |
| forecast | prediction of what the weather will be in the future |
| hygrometer | a weather instrument used to measure humidity |
| meteorologist | scientist who studies the atmosphere and weather |
| nimbus cloud | a dark cloud associated with rain or snow |
| rain gauge | a weather instrument used to measure the amount of rain fall |
| surface map | a weather map that shows weather conditions near Earth's surface; data is shown as symbols |
| wind vane | a weather instrument that shows the direction the wind is coming from |
| Ring of Fire | a place around the Pacific Ocean where many volcanoes and earthquakes happen |
| earthquake | vibrations on Earth's surface caused by sudden movement in Earth, often along a fault |
| volcano | opening in Earth's crust through which magma, gases, and ash reach Earth's surface |
| plates | very large sheets of crust and upper mantle that cover Earth |
