Look around you. It may seem that Earth is perfectly still. But its outer shell or surface is actually moving all the time.

Earth's thin outer shell is broken into big pieces called tectonic plates. These plates fit together like a puzzle, but they're not stuck in one place. They are floating on Earth's mantle, a really thick layer of hot flowing rock.

The flow of the mantle causes tectonic plates to move in different directions. When the edges of plates meet, four things can happen:

2 arrows sliding past each other in opposite directions


image of trees and a house on opposite sides of a fault line

two plates slide
past each other

two arrows colliding into one another


water with land on either side

two plates crash
and fold up

2 arrows moving in opposite directions from each other


magma bubbling up through water with 2 land masses on either side

two plates move apart
from each other

one arrow sinking below the other arrow coming towards it as they collide


1 tectonic plate dipping below the one across from it

one plate sinks
below the other

Even though plates move very slowly, their motion, called plate tectonics , has a huge impact on our planet. Plate tectonics form the oceans, continents, and mountains. It also helps us understand why and where events like earthquakes occur and volcanoes erupt.

Want to explore how plate tectonics affect our world?


Read more about the
Power of  Plate Tectonics

Image Credits:

Illustrations: slip, collision, spreading, and subduction, © AMNH/Eric Hamilton; Earth globe, © AMNH/Eric Hamilton

Images: World Map, courtesy of NOAA; Everest, Ivan Komarov via Wikimedia Commons/CC BY 2.0; Augustine Volcano, Cyrus Read, USGS, Alaska Volcano Observatory/CC0 Public Domain
Sound: Opening, ERH via BY-NC 3.0; mapping earthquakes, ERH via BY-NC 3.0; ending, CC0 Public Domain, ending, CC0 Public Domain; Earthquake, Presidencia de la República Mexicana via flickr/CC BY 2.0