Week 29 - Model of Earth, Sudden Earth Events and Incremental Changes

Tab: Exercise 1.1

Lesson 1.1: A Model for the Earth

ACTIVITY A: Earth Model

Required Readings

Science in Action 7
pages 352 to 356

Science Focus 7

page 382

Welcome to the first module in a very exciting and interesting unit about the Earth and the events that take place on, in and under the crust of the Earth. In the first module you will learn about the basic model that scientists have developed about the structure of the Earth. In the second module, you will learn about fast changes that can take place on the Earth's surface such as earthquakes and volcanoes. In the third module we will examine processes that occur over a very long period of time, but no less change the face of the Earth.

Over the past fifty years geologists have learned more about the structure of the Earth than in all the thousands of years before. One of the main reasons for this is the development of technology that has allowed these scientists to explore deeper and farther than ever before. With the use of satellites and oceanographic research ships, geologists have been able to see the geological processes on the ocean floor. Considering that the greater part of the Earth is covered with water, that's a big step forward. From these studies they have been able to develop a model about the structures inside the Earth. But what does the term 'model' mean? We're not talking about plastic toys here. Read over the section on models in the text, Science in Action, and then fill in the missing words in the paragraph below.
A geologist is a scientist who studies the Earth. They might specialize into many fields such as volcano or earthquake research, or study minerals. This is an ever growing and very interesting field of science.

ACTIVITY B: The Crust of the Earth
The Crust of the Earth is broken into large sections called tectonic plates.

The crust of the Earth could be compared to an iceberg floating in the ocean. Like the iceberg, only a small portion (about one tenth) is seen above the surface and both the crust and the ice burg are moving because of the currents below them. That's right! The Earth's crust is moving all the time. In fact, the crust is not one solid piece, but is broken into many parts called crustal plates. You will learn more about this in the lessons to come. And, like the iceberg, the crust is deepest where the tallest mountains are found.



Well, that's it for this lesson. Now we look at fast changes that alter the Earth's crust. See you there!