Earth Is Made of Plates

Lesson Plan - Get It!

Audio:

Plate tectonics is a scientific theory stating that Earth's crust is divided into large plates on the surface.

These plates are moved by convection currents in the mantle. Convection currents, pictured below, occur when warmer magma is pulled upward, while cooler magma sinks.

_{Image, via Wikimedia Commons, is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported,}

These currents are responsible for pushing and pulling plates, causing collisions along plate boundaries.

There are two types of crustal plates: oceanic and continental. Can you predict which type is more dense? Consider this image:

_{This image has been released into the public domain by its author, Booyabazooka at English Wikipedia. This applies worldwide.}

Which type of plate seems to be sitting lower in the asthenosphere (or mantle)?

If you guessed oceanic, you are correct! Oceanic crust is denser than continental crust. It is made of basalt, an igneous rock that forms at divergent plate boundaries. We'll take a closer look at basalt in just a moment. For now, let's focus on the continental crust, which is made up of granite. It is responsible for creating landmasses and landforms on Earth's surface.

Oceanic and continental plates interact along the edges, or as scientists sometimes call them, boundaries. There are three main types of boundaries that you will investigate further. But first, watch Plate Tectonics Explained from MinuteEarth, for an overview:

Now, build onto that knowledge by creating a foldable:

1. Learn about the three types of plate boundaries by reviewing the USGS and NOAA Resources. Notice that there can be oceanic-oceanic, continental-continental, and oceanic-continental interactions. Be sure to consider and identify each type in the foldable!
2. Organize your learning into a foldable. Fold a sheet of paper in half hot-dog style (long ways).
3. Then, cut three flaps of equal size into one of the halves. Now, you are ready to label!

Use these resources to help understand the three types of plate boundary interactions:

• There are three kinds of plate tectonic boundaries: divergent, convergent, and transform plate boundaries. courtesy of the National Oceanic and Atmospheric Administration
• Understanding plate motions, from the U.S. Geological Survey

• Did you learn anything new?

Happily, plates move very slowly, leading to change over time.

• Can you imagine if plates collided quickly?

In the Got It? section, we will look at plate identification and boundary interactions on Earth's surface.