Crust: Earth's thin, rocky outer layer Mantle: The thick layer of hot rock beneath the crust Outer core: A layer of liquid iron and nickel Inner core: A solid ball of iron and nickel at Earth's center Which Earth layer is thickest?: The mantle Which Earth layer is thinnest?: The crust Continental crust: The thicker crust that makes up the continents Oceanic crust: The thinner, denser crust under the oceans Moho: The boundary between the crust and mantle Troposphere: The lowest layer of the atmosphere, where weather happens Stratosphere: The atmosphere layer above the troposphere, holding the ozone layer Mesosphere: The layer where most meteors burn up Thermosphere: The layer where auroras happen and the space station orbits Exosphere: The outermost atmosphere layer fading into space Ozone layer: A layer that absorbs harmful ultraviolet light Hydrosphere: All the water on Earth Lithosphere: Earth's rigid outer shell Biosphere: All living things on Earth Atmosphere: The blanket of gases around Earth Percent of Earth covered by water, about: 71 percent Percent of Earth's water that is salty, about: 97 percent Mountain: A very high landform with steep sides Hill: A raised landform lower than a mountain Valley: Low land between hills or mountains Canyon: A deep valley with steep sides, often cut by a river Plateau: A high, flat landform Plain: A large flat area of land Mesa: A flat-topped hill with steep sides Butte: A small, steep-sided hill with a flat top Peninsula: Land surrounded by water on three sides Island: Land completely surrounded by water Isthmus: A narrow strip of land connecting two larger landmasses Archipelago: A group of islands Delta: Land built up where a river empties into a larger body of water Cape: A point of land that sticks out into water Bay: Part of the sea that curves into the land Gulf: A large bay Strait: A narrow waterway between two larger bodies of water Lake: A body of water surrounded by land River: A large stream flowing to a lake or sea Tributary: A stream that flows into a larger river Source of a river: Where a river begins Mouth of a river: Where a river ends Watershed: The area of land that drains into a river Dune: A hill of sand made by wind Cave: A natural hollow in rock or ground Cliff: A steep rock face Glacier: A large, slow-moving river of ice Iceberg: A large floating piece of ice broken from a glacier Oasis: A fertile spot in the desert with water Reef: A ridge of coral or rock near the surface of the sea Atoll: A ring-shaped coral island Fjord: A long, narrow sea inlet between steep cliffs Tundra: A cold treeless plain Prairie: A large grassy plain Basin: A low area where water collects Elevation: Height above sea level Topographic map: A map showing the shape and height of land with contour lines Contour line: A line on a map connecting points of equal elevation Longitude: Distance east or west of the Prime Meridian Latitude: Distance north or south of the Equator Equator: The imaginary line at 0 degrees latitude around Earth's middle Axis: The imaginary line Earth spins around Rotation: Earth spinning, one turn each day Revolution: Earth traveling around the Sun, one trip each year Earth's axial tilt: About 23.5 degrees Cause of the seasons: Earth's tilted axis as it orbits the Sun Solstice: The day with the most or least daylight in a year Equinox: A day when day and night are nearly equal Free flashcards from Peabody at peabody.kids/flashcards/earth-layers-landforms