Igneous Rocks

advertisement

Colleen Fadden

Renee Pollard

Andrea Popolizio

Igneous rocks are the oldest type of rocks.

Deep inside the earth where it is very hot, there is melted rock called magma.

As the magma comes up to the surface, it starts to cool and turns into solid igneous rock.

All igneous rocks do not cool the same way, that is why they do not look all the same.

Depending on how the rocks cool, they are classified as either intrusive or extrusive.

Intrusive igneous rock is formed when the magma cools slowly deep under the earths surface, causing large crystals

Extrusive igneous rock is formed when the magma comes from the volcano and reaches the earth’s surface through big cracks. The lava cools fast cause small crystals.

Normally contains no fossils

Rarely reacts with acid

Usually have no layering

Usually made of two or more minerals

May be light or dark colored

Usually made of mineral crystals of different sizes

Sometimes have openings or glass fibers

May be fine-grained or glassy (extrusive)

Granite

Pumice

Obsidian

Pegmitatite

Sedimentary rocks are rocks that are formed by sediments from the earth pressed together. This usually occurs underwater.

Sediments are small pieces of rocks.

Sedimentary rocks are formed by broken pieces of rocks that pile up.

When the sediments pile up they form layers.

Over a long period of time, the pieces pile up and get pressed together to for rocks.

Contain fossils most of the time

React with acid

Have layers

Made up of pieces cemented of pressed together

Contain a variety of colors

Particle sizes are sometimes different

Examples of Sedimentary Rocks

Sandstone Limestone

Shale Coal

Metamorphic rocks are rocks that have been changed.

They are formed deep within the Earth.

Metamorphic rocks were once igneous and sedimentary rocks.

They are the least common of the three types of rocks.

Metamorphic rocks are formed when heat and pressure are applied to sedimentary and igneous rocks.

The heat and pressure cooks the rocks and changes their structure.

The chemical changes that take place are what makes the appearance of rocks very different.

To demonstrate how metamorphic rocks are formed, try this:

• Squeeze you hands together very hard. You will begin to feel heat and pressure. When the

Earth’s crust moves, the heat and pressure cause the rocks to squeeze together so hard that the rocks change shapes.

There are two types of metamorphic rocks: foliated and non-foliated.

Foliated metamorphic rocks have layers, or banding.

Examples of foliated metamorphic rocks are:

• Slate

Schist

Gneiss

Non-Foliated Rocks are not layered

Examples of non-foliated rocks are:

• Marble

Quartzite

Marble

Gneiss

Quartize

Marble

Now it’s time to use what you have learned for an activity!

Today you will explore some rocks. You’ll sort the rocks and discuss them with your partner.

See what new things you can discover!

Science notebook

The Observing Rocks Worksheet

1 hand lens

1 magnet

1 set of 12 rocks

1 cardboard tray

Yourself

1.

Think about your senses.

How many senses do you have?

What information do you get from using each one?

2. Explore the 12 rocks in front of you using all of your senses except taste. Describe to your partner what you see/feel/smell.

Write the answers to the following descriptors in each of the small boxes about

 each numbered rock.

What is its color?

Is it magnetic?

Does it have any fossils?

3. Next, sort the rocks any way you choose.

Think about why you sorted them that way. Share with your partner. Write down the way you sorted them in Box 2 of your worksheet.

4. Discuss with your partner the reasons you grouped your rocks how you did.

Can they be sorted another way? Put the rocks back in the middle and find another way to separate them. Write down the second way you separated the rocks in Box 3 on the worksheet.

5. Review how you separated the rocks.

Write down the properties/ the ways you described and separated the rocks on the lines at the bottom of your paper.

Here are two links to lessons/activities about rocks

 http://www.bbc.co.uk/schools/scienceclips

/ages/7_8/rocks_soils.shtml

- This website allows you to virtually test different properties of rocks.

 http://www.gamequarium.org/cgibin/search/linfo.cgi?id=9686 – This is a link to a Magic School Bus episode about rocks and erosion.

Here are two links to lessons/activities about rocks

 http://www.bbc.co.uk/schools/scienceclips

/ages/7_8/rocks_soils.shtml

- This website allows you to virtually test different properties of rocks.

 http://www.gamequarium.org/cgibin/search/linfo.cgi?id=9686 – This is a link to a Magic School Bus episode about rocks and erosion.

 http://library.thinkquest.org/J002289/roc ks.html# http://www.kidsgeo.com/geology-forkids/0028-metamorphic-rocks.php

http://www.rocksforkids.com/RFK/howro cks.html#Metamorphic http://www.historyforkids.org/sciencefor kids/geology/rocks/metamorphic/

Download