Download Rock cycle and Rocks made simple

Structure of the Earth
Sedimentary rocks are formed when different layers of sediments join together over a
long period of time. These rocks can be found on the surface of the earth or lithosphere.
Rocks on the surface of the earth keep changing and recycling. However, this is a very
slow process and takes a long time for the rocks on the Earth’s surface to move down
towards the centre of the Earth.
1. Visit the following website and then label the following diagram. Give a short
description for each part.
http://mediatheek.thinkquest.nl/~ll125/en/struct.htm
The outermost layer is called the crust. It only makes up 1% of the earth’s weight. The
mantle is the next layer. It is a hot dense layer of rock. Most of the earth’s internal heat is
located in the mantle. The final layer of the earth is the crust. It makes up nearly one third
of the earth’s weight. The core is made out of two parts, the outer core and the inner core.
The liquid outer core is 2200 km thick. The solid inner core is 1250 km thick. The outer
core is made out of iron and is very dense. The inner core is made up of solid iron and
nickel.
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The following website shows the rock cycle. Click on different parts of the rock cycle
diagram for more information. If you find the information a little hard to understand here
is what you can do: look above the page on your left hand side and click on the beginner
for simpler explanation.
http://www.windows2universe.org/earth/geology/rocks_intro.html
You can also find the same information in the ‘Rock cycle’ program. Use this program
and give at least two examples for each type of rock that you are learning about. Write a
short description for each type of rock.
1. Sedimentary rocks
Sedimentary rocks form at the earth’s surface. About three quarters of the earth’s surface
is made up of sedimentary rocks. Clastic sedimentary rocks are a type of sedimentary
rock that is made from broken pieces of rock. The broken pieces of rocks are called
sediments. Sediments are the sand on the beach, the mud in the bottom of a lake and the
pebbles in a river.
2. Igneous rocks
When molten rocks cool and harden they form igneous rocks. Molten rock is magma
when it is beneath the surface of the earth and lava when it’s above the surface of the
earth. Igneous rocks are classified into two groups. Igneous rocks that form above the
surface are called extrusive igneous rocks. Igneous rocks that form below the earth’s
surface are called intrusive igneous rocks.
3. Metamorphic rocks
A metamorphic rock is a rock that gets changed by heat or pressure. When a rock is
metamorphosed (changed) its mineral crystals are changed. A good place for rocks to
metamorphose is somewhere the earth’s tectonic plates are coming together. The reason
they can metamorphose here is because it’s very hot and the pressure is high.
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Activity:
1. Open the following program (rock cycle (labeling activity)) and see if you can
label the diagram.
2. Now open the following program’ Pearson Rock cycle’ and explain how rocks
can be changed from one form to another.
A metamorphic rock can melt into magma and lava. Due to volcanic activity it
turns into an igneous rock. After that, due to erosion it is broken up into
sediments. Finally due to deposition, it turns into a sedimentary rock.
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