Page 122 - Science Course 2 (Book 2)
P. 122
The Ever-Changing Surface of Earth Mo11-L1a: What is Plate Tectonics?
Lesson 1
continental drift
In this topic, you will learn the following Wegener’s hypothesis that suggests the continents
lessons: are in constant motion on Earth’s surface.
Mo.11–L1a: What is Plate Tectonics?
Mo.11–L1b: What Forces Change Earth’s
Surface?
Mo11-L1a What is Plate Tectonics
KEY CONCEPTS:
1. What is the theory of plate tectonics?
2. What evidence do scientists use to support the
theory of plate tectonics?
Vocabulary A-Z
Let us learn some vocabulary Let’s Begin
Plate Tectonics Plate Motion
theory that Earth’s surface is broken into large, rigid
pieces that move with respect to each other. The theory of plate tectonics states that Earth’s
crust is broken into rigid plates that move slowly
over Earth’s surface.
The rigid plates are called tectonic plates.
North America is part of the North American Plate.
The movement of one plate is described as either
moving away from or toward another plate, or sliding
past another plate.
Plates move at speeds of only a few centimeters per
year.
At this rate, it takes moving plates millions of years
to make new continents, new mountain ranges, or
other landforms.
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