1. Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
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2. Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Earthquake!
Shaken Up
An earthquake is a shaking of Earth’s surface that can cause land to rise and fall.
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3. Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Earthquake!
Shaken Up
Most earthquakes are too weak to be felt, but strong earthquakes can cause big changes to Earth’s surface.
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4. Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Shaken Up
Earthquakes happen because of movements in the Earth’s crust.
They occur mostly in places where two pieces of crust meet.
Pieces of crust push together, pull apart, or slide past each other.
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5. Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Volcano!
Feel the Heat
A volcano is a mountain made of cooled lava, ash, or other materials from eruptions.
Like earthquakes, volcanoes are caused by movements of Earth’s crust.
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6. Feel the Heat In some places, one piece of crust slides under another.
Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Feel the Heat
In some places, one piece of crust slides under another.
This causes the rock underground to melt. This melted rock, called magma, moves upward.
If it reaches an opening, it will erupt onto Earth’s surface. The melted rock is then called lava.
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7. Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Feel the Heat
As the lava cools, it gets hard. Some volcanoes grow larger with every eruption.
In some volcanoes, lava gently oozes out. Other volcanoes explode!
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8. Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Feel the Heat
Lava, stone, and ash are thrown from the volcano’s opening with tremendous force. Exploding volcanoes can quickly change the Earth’s surface.
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9. Big Changes Fire, Water, Mud A forest fire starts small.
Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Big Changes
Fire, Water, Mud
A forest fire starts small.
It can be sparked by lightening, a bit of lava, or a careless person.
It is important to act quickly to control forest fires.
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10. Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Fire, Water, Mud
Too much rain in a short period of time can cause a flood.
A flood is a change that happens when streams, rivers, or lakes get too full and overflow.
Entire towns can be destroyed. Over time, floodwater drains away, dries up, or is absorbed into the ground.
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11. Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Fire, Water, Mud
Sometimes, water from rain or a flood loosens dirt on the side of a hill or mountain.
The dirt slides downhill in a mudslide or landslide.
It may bury part of a town.
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12. Be Prepared Planning Ahead How do you prepare for a disaster?
Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Be Prepared
Planning Ahead
How do you prepare for a disaster?
You make an emergency plan and prepare your home.
You make sure any pets will be safe, too!
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13. Planning Ahead People do many things to prepare for disasters.
Unit 5 Lesson 4 How Does Earth’s Surface Change Quickly?
Planning Ahead
People do many things to prepare for disasters.
Buildings are designed to withstand earthquakes. Rivers are built up to prevent floods.
Emergency plans can help keep us safe. Families can talk about what to do in an emergency.
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