Lesson Plan - Get It!
We recycle plastic, paper, cans, and many more items. Recycling is a great way to protect the earth and keep it (and us) healthy. You may be surprised to learn that the earth even recycles! How exactly does this occur? Continue with the lesson to find out more!
The earth's crust is the layer of the earth that we live on.
The crust, as hard as it is, breaks into pieces called tectonic plates. The world map below shows the names and locations of the tectonic plates (Check out our lesson under Additional Resources to learn more.).
Some plates move away from each other, creating what's known as a divergent boundary. Most divergent boundaries are actually on the ocean floor. As the plates spread apart, underwater volcanoes form.
Look at this picture of a divergent boundary. Take notice of the direction the two plates are moving; they are moving away from each other, or diverging.
There are two types of crust: continental crust and ocean crust. You have probably guessed that continental crust is under the continents, and oceanic crust is under the ocean. Besides their different locations, they differ in what they are made of.
Ocean crust consists of basalt, a material more dense than granite. Ocean crust is thinner than continental crust, which is made of granitic sedimentary and metemorphic rock, and is younger (You will find out why in the Go! section.). The Pacific Ocean is on a huge oceanic plate called the Pacific Plate.
Basalt is dense rock, more dense than the rock that makes up the continental crust.
To understand the concept of density, move on to the Got It? section, where you will participate in a density experiment using household items.