| A | B |
|---|
| Maritime tropical | air mass that forms over the oceans near the equator |
| Maritime polar | air mass that forms over the oceans near the poles |
| Continental tropical | air mass that forms over land near the equator |
| Continental polar | air mass that forms over land near the poles |
| Air mass | a huge body of air that has similar temperature, pressure, and humidity throughout |
| Front | the area where air masses meet and do not mix |
| Cold front | a quickly moving front that causes abrupt weather changes; forms when a rapidly moving cold air mass runs into a slowly moving warm air mass, pushing the warm air upwards |
| Warm front | a slowly moving front causing a period of rain or fog; forms when a moving warm air mass slides over a slowly moving cold air mass |
| Stationary front | forms when a cold and warm air mass meet, but neither one has enough force to move the other; produces many days of clouds and precipitation |
| Occluded front | cut off, as the warm air mass at an occluded front is cut off from the ground by cooler air beneath it |
| Cyclones | a swirling center of low air pressure |
| Anticyclones | a high-pressure center of dry air |
| Tornado | a rapidly whirling, funnel-shaped cloud that reaches down from a storm cloud to touch Earth's surface, usually leaving a destructive path |
| Hurricane | a tropical storm that has winds of 119 kilometers per hour or higher; typically about 600 km across |
| Meteorologists | scientists who study the causes of weather and try to predict it |
| Tropical rainy | a type of climate existing near the equator in which the temperature is always 18C or above |
| Dry | a climate in which the amount of precipitation that falls is less than the amount of water that could potentially evaporate |
| Temperate marine | a climate zone found along the coasts of continents in the temperate zones |
| Temperate continental | a climate region found in the Northern Hemisphere in which extreme temperatures occur |
| Polar | the coldest climate region found in the far north and south |
| Rotation | the spinning motion of a planet about its axis |
| Retrograde rotation | the spinning motion of a planet from east to west, opposite to the direction of rotation of most planets and moons |
| Revolution | the movement of an object around another object |
| Orbit | the path an object takes as it revolves around another object in space |
| Axis | an imaginary line that passes through a body's center and the North and South Poles, about which it rotates |
| Solstice | the two days of the year on which the noon sun is directly overhead at either 23.5 degrees South or North |
| Equinox | the days of the year on which neither hemisphere is tilted toward or away from the sun |
| Vernal equinox | the day of the year that marks the beginning of spring in the Northern Hemisphere |
| Autumnal equinox | the day of the year that marks the beginning of the fall in the Northern Hemisphere |
| Inertia | the tendency of a moving object to continue in a straight line or a staionary object to remain in place |
| lunar eclipse | the blocking of sunlight to the moonthat occurs when Earth is directly between the sun and them moon |
| solar eclipse | the blocking of sunlight to earth that occurs when the moon is between the Earth and the sun |
| umbra | the darkest part of a shadow; the inner shadow |
| penumbra | the part of the shadow surrounding the darkest part; the outer shadow |
| gravity | the attractive force between 2 objects; its magnitude depends on their masses and the distance between them |
| satellite | any object that revolves around another object in space |
| geosynchronous orbit | the orbit of a satellite that revolves around Earth at the same rate that Earth rotates |
| geocentric | a description of the solar system in which all of the planets revolve around Earth |
| heliocentric | a description of the solar system in which all of the planets revolve around the sun |
| ellipse | an elongated circle, or oval shape; the shape of the planets' orbits |
| nuclear fusion | the combining of 2 atomic nuclei into a single larger nucleus, as when 2 hydrogen atoms join together to form helium, releasing energy |
| sun's core | the center part of the sun where nuclear fusion occurs |
| photosphere | the inner layer of the sun's atmosphere |
| chromosphere | the middle layer of the suns's atmosphere |
| corona | the outer layer of the sun's atmosphere |
