5th Grade Science
Harcourt Science
Unit C

Chapter 1: Lesson 2 - pp. C14 - C19

Processes That Begin Inside the Earth

Mountains - form where continental plates collide. The plates push together, their edges crumple and fold into mountains.

Volcano - a mountain formed by lava and ash. Lava is magma that reaches earth surface. Ash is small hardened lava.

Earthquake - is caused by the sudden release of energy called seismic waves in the Earth’s crust. This energy causes the ground to shake. Most earthquakes occur at plate boundaries.

Earth Has Three Layers

Crust - is the outer layer of the Earth made of rock.

Mantle - is the layer of rock beneath the Earth’s crust. The mantle is very hot. It is solid just under the crust, so part of the mantle is soft like melted candy.

Core - the core of the earth is the center of the Earth. You can divide the core into 2 parts called the inner core and the outer core. The inner core is solid because of the great pressure in the center of the Earth, the outer core is liquid, or molten because of the intense heat in the center of the Earth.

You will be asked to illustrate the Earth’s layers and the processes listed above, so be sure to study the diagrams found in your text book.