Lesson 1:  What is Inside a Rock?

In this lesson from the book "Earth Beneath Your Feet", you will learn what rocks are made of, what makes rocks different colors, and what makes rocks hard or soft.

Rock Observations

Copy the link below and paste into the Photon App.


Look at the 12 rocks in your egg carton.  Open Keynote and create 1 slide each for rocks 1, 2, and 3.  On each slide take a picture of your rock and record what you notice of its color, shape, shine, weight and hardness.  This can be done on your own or with a partner.  Now group and classify the 12 rocks in some way.  Try to group them in a different way.

Click on the link below to watch a Brain Pop video on Rocks and Minerals.

Rocks are Made of Minerals

In your rock observations you saw that rocks are different and are made of different things.  Some of these things you saw are called minerals (click to find out more about what a mineral is).  Minerals are solids that form naturally.  They are not plants or animals.  They give rocks their different colors and make the rock hard or soft.

There are over 3,000 kinds of minerals and every one of them has its own color, hardness, and crystal shapes.  These are the properties (click to find a list of the properties and what they are) of minerals.  We use minerals for different reasons based on their properties.  Try the activities below:

Create a definition slide for each of the following words: rock, mineral, and property.

Let's Test Some Rocks - copy the link below and paste into the Photon App.


Rock Adventure Activity - copy the link below and paste into the Photon App.


Properties of Minerals

Hardness:  You can tell how hard a mineral is by scratching it. It is considered soft if you can scratch it with a fingernail. It is considered hard if a steel nail will not even scratch the mineral.  For example graphite is a soft mineral.  That is why people use it in pencils.  It will always leave its mark!

Color and Shine Another property of minerals is color.  Geologist use a streak test (rubbing the mineral on a tile) to see the true color of the mineral.  Shine is also a property.  Some minerals are dull or waxy and others are metallic, looks like metal.  

Breakage/Cleavage Looking at your minerals, you will notice that they come in different shapes.  This is because minerals break differently.  Diamonds break with flat sides, allowing for a beautiful stone.  People use diamonds in jewelry for its beauty and hardness.