|Is the Earth always changing?||
Erosion by water and wind help form the Grand Canyon.
|The Earth is changing constantly. Some changes happen quickly and are easy to see. An earthquake can change the landscape of a city in a few seconds. A sandstorm can cover a large area with sand in a few hours. A hurricane can destroy a beach or town in a few hours.
Most changes occur very, very slowly, so you can't see them all. For example, North American and Africa were once joined together as part of the supercontinent Pangaea . Pangaea separated into smaller continents about 200 million years ago with the opening of the Atlantic and Indian oceans. Africa and North America have been moving away from each other at the rate of 2.5 centimeters (1 inch) per year. That's how fast your fingernails grow! The surface of the Earth is always changing in so many ways that we can't see.