GO_Plate Tectonics Lesson
Let's take a tour through Earth's layers, shall we? It's like peeling the layers of an onion, but this onion is a massive, complex planet. As we embark on this tour, we'll uncover the mysteries of Earth's layers, the dynamics of plate tectonics, and how these plates interact with one another.
Watch the following video to learn about the layers of the Earth.
How are we sure this is actually happening?
So, yes - this is a theory. But - we have some evidence to back it up!
There's some pretty cool evidence that scientists have gathered over the years.
One piece of evidence is like a big Earth puzzle!
About 300 million years ago, all the continents were like pieces of a giant jigsaw puzzle called Pangea. This idea was first suggested by a scientist named Alfred Wegener. He noticed that if you fit the coastlines of South America and Africa together, they match up almost perfectly. It's like they used to be connected! Even though people didn't believe him at first, further research has shown that Wegener was onto something big.
Here's another clue: fossils!
Fossils are ancient plant and animal remains that turn into rock over time. When scientists looked at fossils on continents that are now far apart, they found something amazing. Fossils of the same plants and animals were found on continents that seemed like they were once connected. How could the same fossils be on continents that are now oceans apart? The answer is that these continents used to be next to each other, and they've slowly moved apart over millions of years. This is strong evidence that Earth's tectonic plates are indeed shifting, and it's part of what we call plate tectonics.
So, thanks to clues like fitting continents and matching fossils, we're pretty sure our planet's surface is constantly changing!
There are two major theories about how Earth's tectonic plates move.
The first one suggests that it's all about mantle convection.
Picture a boiling pot of water on your stove – the hot water at the bottom rises, creating a circular flow, just like a whirlpool. In Earth's case, heat from the core moves to the mantle, causing convection. The mantle, even though it's solid rock, behaves like a slow-flowing fluid under constant force. This convection is a big player in tectonic plate movement. When the mantle moves horizontally beneath the crust, it drags the plates with it, making them spread apart (diverge) when convection currents rise and collide (converge) when they sink.
Now, the other theory throws ridge push and slab pull into the mix.
Yes, it still relies on mantle convection, but there's more to it. Plates are moved by two forces: the weight of one part of the plate diving into the mantle (slab pull) and the push from ocean ridges where new crust forms (ridge push). This model has some solid backing, like faster-moving plates that are attached to subducting slabs. But here's the twist – mantle convection is still crucial. Without it, there'd be no ridges to push against because convection brings hot rock up to form those ridges. Plus, many plates, like the North American Plate, move steadily (though slowly) without much slab pull.
So, the real answer might be a mix of these theories!
What happens when these plates interact with each other?
There are three different ways that plates can interact with one another, including convergent, divergent, and transform plate boundaries. Below, we will discuss each of the following.
Select each type of boundary below to learn more.
Test your knowledge with the practice below:
Earth is composed of several layers, including the crust which is the solid surface beneath our feet with two main types: continental and oceanic. These plates interact in three main ways: they can diverge (move apart), converge (come together), or slide past each other (transform boundaries), leading to a variety of geological events and landforms.
UP NEXT: Hazards of Plate Movements
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