An imaginary line that runs through the Earth's center from the North Pole to the South Pole

A complete trip of Earth around the sun

The layer of gases surrounding the Earth

One or two days of the year when the sun reaches its northernmost or southernmost point (longest day in the summer, shortest day in the winter)

One or two days each year when the sun is directly overhead at the Equator (day and night are equal)

The average weather in an area over a long period of time

The water that falls on the ground as rain, snow, sleet, hail, or mist

An area that receives reduced rainfall because it is on the side of a mountain facing away from the ocean

A large, unbroken mass of land (there are 7 on Earth)

One of the 16 pieces of Earth's crust

A place where two tectonic plates grind against each other

An event in which the ground shakes or trembles, brought about by the collision of tectonic plates

A long, narrow band of volcanoes surrounding the Pacific Ocean (also the name of a Johnny Cash song)

A giant ocean wave caused by volcanic eruptions or movement of the earth under the ocean floor

The process by which Earth's surface is worn away by natural forces

The process by which weathered bits of rock are moved elsewhere by water, wind, or ice

A large body of ice that moves slowly across land

A flat area that rises above the surrounding land

A large expanse of land that can be flat or have a gentle roll

A narrow strip of land that connects two larger land areas

The part of a continent that extends into the ocean in a plateau, then drops sharply to the ocean floor

A long, narrow, steep-sided cut on the ocean floor

A process that makes salt water safe to drink

The water contained inside Earth's crust

An area where sand, silt, clay, or gravel is dropped at the mouth of a river

The process in which water is used and reused on Earth, including precipitation, collection, evaporation, and condensation

The change of liquid water to water vapor

The result of water vapor changing to a liquid or a solid state

Rain that contains harmful amounts of poisons due to pollution