Earth Video Quiz

An earthquake occurs when the stress below the surface causes areas on either side of the fault line to move. When this happens the energy that is released is in the form of _____. If the disturbance is big enough, the force will eventually cause damage on the surface of the earth.

In some areas of the earth, rock can be out in the open and seem to have been formed in layers. This third category is called _____ rock and was formed as layers and layers of rock were piled upon one another. From this category we get such natural resources as coal and oil. Some of the rocks in this group are called fossils and consist of the remains of plant and animal life.

Our earth is an ever-changing place. Changes are often results of what happens below the surface. The earth's interior consists of several different layers. The inner core is thought to be made of _____.

The uppermost layer of the earth is the region we live on. This layer, called the _____, is affected by what is happening beneath it. The many geologic formations, like volcanoes and mountains, were formed by forces acting beneath this upper layer of the earth.

The earth's huge plates have been moving very, very slowly. The movement is so slight that it is not seen happening. Scientists believe that this process of movement, called _____, is a major cause of geologic changes on our planet.

The crust would look quite different if we could strip away the oceans and plant life. In many places the crust is cracked. The large pieces of the crust are called _____. The continents rest upon them and, over millions of years, have actually moved.

The grinding of the earth's plates has been going on for millions of years. One result of this process is a crack in the earth's surface, called a _____. One side of this crack tries to move in one direction while the other moves in the opposite direction. The earth's plates remain in position until stress from below causes them to move.

The outer core consists of rocky material and is very hot and under great pressure. The next layer, called the _____, consists of a hot, lava-like area on the inside and a solid outermost portion.

Deep within the earth, rocks are under a great deal of heat and pressure. Another type of rock, called _____ rock, is formed by such heat and pressure. Sometimes this type of rock is formed by changes in other types of rock. For example, limestone is changed to marble by heat, pressure and time.

Scientists classify rocks according to how they were formed. One type of rock, called _____ rock, was formed by the cooling of a hot liquid material called magma. There are a number of different types of this rock and one such type is called granite. This rock is frequently used as building material.