Forces that shape the Earth Plate Tectonics Plate Tectonics 2

What causes Earth’s features to change? Earth’s features are constantly changing! Sometimes it happens rapidly and other times it happens over a very long period of time. Sometimes new features are being formed and sometimes old features are being beaten up.

I Can By the end of this lesson you should be able to answer the question: How does the earth change? So, pay attention as we go through these different landforms, or surface features, to find out how they are constantly changing. Be sure to tell me the 3 different types of plate movements by the end of this lesson.

Earth’s Crust These are the different layers of the Earth and the deeper we go into the Earth, the hotter it gets. The outermost layer of the Earth is called the Crust. It is very thin compared to the other layers. The crust includes the 7 continents and the land found under the ocean. The crust is made up of solid rock. Let’s point to and name the 7 continents which are part of Earth’s crust. North America South America Africa Asia Europe Australia Antarctica

Inside Earth The inside of Earth is very hot! Heat and pressure underneath the crust cause materials inside the Earth to move and these movements cause changes on the Earth’s crust. These are the changes we are going to talk about.

Plate boundaries The crust is not just one giant piece. It is actually broken up into pieces called plates. The plates float on the partly melted rock underneath it. The plates have 3 basic types of movements: They can bump into each other, pull apart from each other, or slide past each other. Look at this map. Can you identify where the plates are and where they meet? Wherever you see these neon green lines, that is where the plates meet. This is called a plate boundary.

Let’s Practice: 1. Take your hands and make 2 fists. Now hold your hands together- knuckle to knuckle. Slowly pull your hands apart. This is the first type of plate movement. 2. Take your hands and make 2 fists. Now bump them into each other. This is the second type of plate movement. Take your hands and make 2 fists. Now hold your hands together- knuckle to knuckle. Slowly glide your hands back and forth as you rub knuckle to knuckle This is the third type of plate movement.

Quick Check: True or False: The Earth’s crust is made up of one large sheet of thin solid rock. False! The Earth’s crust is made up of several plates.

Quick Check: What are the three types of plate movements? They can bump into each other, pull apart from each other, or slide past each other We will learn the name of these movements in a moment!

First Type of Plate Movement Divergent

Take your hands, make fists and slowly pull them apart from each other. Plates sometimes move apart from each other and the movement of the plates causes a crack in the Earth’s crust.

Divergent: If the land moves down between the crack, or fault, it forms a landform called a rift valley. Who would like to come up here and show me where the valley is?

Quick Check: What is it called when land comes and fills in the space left between a divergent gap? Rift Valley!

Divergent: If the opening in the Earth’s crust lets melted rock, ash, and gases escape we call that a: If these materials suddenly release from the volcano it is called an: Volcano! Eruption!

What do you think forms when…. A volcano erupts, melted rock (called lava) pours out, and when it reaches the surface it cools and hardens. Then it starts to pile up around the opening. Later on, another eruption can repeat this process: erupt, pour out, harden. Erupt, pour out, harden. Over time the eruptions can build a: Mountain! Yes, this is one way a mountain can form. volcanoes

Did you know? Many divergent boundaries are found under the ocean! Volcanoes can build up mountains from the ocean floor and when they grow up tall enough to poke out of the ocean, they become volcanic islands. This is how the Hawaiian Islands were formed.

Quick Check: True or False: Volcanic Eruptions can form mountains and islands. True!

Second Type of Plate Movement Convergent

1. Take your hands and make 2 fists. Now bump them into each other. The highest mountains form when two plates bump or crash into each other. The plates push against each other. This squeezes the land and pushes it upward. The layers of rocks form folds and the top of the folds become mountains.( Folded Mountain) Example: The Himalayas in Asia, The Andes in South America, The Alps in Europe, and the Rocky Mountains in North America.

Quick Check: Give me one example of a folded mountain caused by convergent plates The Himalayas in Asia, The Andes in South America, The Alps in Europe, and the Rocky Mountains in North America.

Convergent Sometimes one plate can move under the other- called subduction and this can cause multiple things to happen. 1. The area can start to shake from all of the folding and bending of plates as they crash into each other. This is called: 2. As the plate digs into the Earth, it can open up the hot interior and if that hot melted rock reaches the surface it can erupt through and we have (again): Earthquake! Volcano!

Quick Check: Shaking that can be felt on the surface of the Earth and occurs from the movement of Earth’s plates is called: An Earthquake!

Question: Why do you think volcanoes are found and earthquakes happen in states such as California, Oregon, Washington, and Alaska? This is where plates meet! And they can push and pull the Earth’s crust!

Third Type of Plate Movement Transform

Take your hands, make fists, and rub them against each other. At transform boundaries, the plates slide past each other but don’t crunch or tear into each other so you wont find volcanoes here. But, as these plates shift past each other their sliding motion can cause some violent shakes in the Earth called: earthquakes Earthquake!

Transform One of the most famous faults has occurred along a transform boundary: San Andreas Fault

Quick Check: What type of movement is a divergent movement? Plates move away from each other!

Quick Check: What type of movement is a convergent movement? Plates move toward each other!

Quick Check: What type of movement happens along a transform boundary? Plates slide past each other!

Quick Check: Turn to a Partner: List some changes that can happen to the Earth’s surface because of plate tectonics or plate movements. Earthquakes Rift Valleys Mountains Volcanoes Faults Islands

Credits: Fonts: The Wizard of Boz Boz Boz Frames: 3am teacher: