| A | B |
|---|
| Geography | The study of the earth in all its variety. |
| Landform | Individual features of the land, such as mountains and valleys. |
| Environment | Natural surroundings. |
| Global Positioning System | Special device that receives signals from satellites. |
| Geographic Information Systems | Specical computer software that helps geographers gather many different kinds of information about the same place. |
| Artifact | Tools, pottery, paintings, weapons, and other items. |
| Fossils | Remains of humans. |
| Solar System | Earth, eight other planets, and thousands of smaller bodies that all revolve around the sun. |
| Orbit | To travel along something's own path. |
| Atmosphere | The layer of air surrounding the Earth. |
| Axis | Imaginary line that runs through the Earth's center. |
| Revolution | Motion Earth makes that defines a year. |
| Leap Year | A year that contains and extra day every four years. |
| Summer Solstice | The day with the most hours of sunlight and the fewest hours of darkness in Northern Hemisphere. |
| Winter Solstice | The day with the fewest hours of sunlight in Northern hemisphere. |
| Equinox | When day and night are of equal length in both hemispheres. |
| Core | In the center of the Earth made of hot iron mixed with other metals and rock. |
| Mantle | Surrounds the core; a layer of rock about 1,800 miles thick. Remains solid. |
| Magma | Melted rock that flows to the surface during a volcanic eruption. |
| Crust | Uppermost layer of the Earth, is relatively thin, and includes the oceans floors. |
| Continents | Seven massive land areas |
| Plate Tectonics | Theory that the Earth's crust is not an unbroken shell but consists of plates, or huge slabs of rock, that move. |
| Earthquake | Violent and sudden movement of all the Earth's crust. |
| Tsunami | Undersea earthquakes that cause huge waves. |
| Fault | Cracks in the Earth's crust caused by plates sliding together. |
| Weathering | The process of breaking surface rock into boulders, gravel, sand, and soil. |
| Erosion | The process of wearing away or moving wewathered material. |
| Glacier | Giant, slow-moving sheets of ice. |
| Elevation | Height above sea level. |
| Plain | Low-lying stretches of flat or gently rolling land. |
| Plateau | Flat but have higher elevation; some have steep cliff forms on one side where rises above nearby lowlands. |
| Isthmus | A narrow piece of land that connects two larger pieces of land. |
| Peninsula | A piece of land with water on three sides. |
| Island | A body of land smaller than a continent and completely surrounded by water. |
| Continental Shelf | Plateau off each coast of a continent that lies under the ocean and stretches for several miles. |
| Trench | Valley in the ocean floor. |
| Strait | Narrow body of water between two pieces of land. |
| Channel | Body of water wider than a strait between two pieces of land. |
| Delta | Area formed from a soil deposit located at the mouth of a river. |
