By Susan M. Frack
BACKGROUND:
Scientists have identified over 2000 different minerals in the earth's crust. 95% of the earth's crust is composed of about a dozen different rock-forming minerals. The rocks composed of these minerals can be formed in three different ways. Scientists can learn many different things about a rock by observing and classifying it.
In this investigation you will become very "friendly" with the rocks in your bag as you group them in different ways.
MATERIALS:
- 1 bag of rocks
- pencil
- magnifying glass
- 1 sheet of newspaper
PROCEDURE:
- Cover desk with newspaper.
- Spread out your rocks and look them over. Divide them into 3 different groups. Describe your groupings below.
- Discuss the groupings with the rest of the class. Listen and share ideas.
- Investigate the rocks by looking at color. Divide the rocks into 3 groups and list below, describing how you grouped the rocks.
- Now use the magnifying glass and investigate the rocks. Regroup them into 3 groups and describe below how you grouped them.
- Investigate the texture of the rocks. Divide the rocks into 3 groups. Describe your groups below:
- Investigate the rocks, looking for layers. Describe your groups below.
CONCLUSIONS:
- Review your lists of rocks for each investigation. Are they the same or different? Explain your answer.
- Is it possible to correctly classify a rock by using/looking at only 1 characteristic? Explain your answer.
- Which two of the characteristics that you investigated do you feel would be most beneficial to use to correctly identify a rock sample? Explain your answer: