IF ROCKS COULD TALK!

You now know that the Calvert Cliffs is made of layers of sediment that built up over millions of years. These sediments helped to create the rocks found in the cliffs. But are all of the rocks that make up the cliffs exactly the same? In order to better understand what the rocks in the cliffs can tell you about Maryland’s past, you will need to gather some general information about the characteristics of different rocks.

 

Objective

When you have completed this investigation, you should be able to

1. analyze different rock characteristics in order to describe features that can be used to distinguish among different types of rocks.

 

Activity 1:

In your quest to gather information about rocks, you decide to get some expert advice from Dr.

Antropologist. Here’s what he has to say:

 

Oh, yes, rocks indeed can provide many clues to Maryland’s past. But

you must remember, even though many rocks look the same, they can be

very, very different. In order to have an idea about what the conditions

were like when the rocks formed, you need to study their characteristics.

I’ve sent some different rock samples to your teacher. Take a moment to

look at some of the rocks features. Then, use the resources I’ve given

your teacher to discover more about rock characteristics. Later!

 

1. Observe the different rocks provided by your teacher.

2. Brainstorm a list of the different characteristics you could use to classify the different types of rocks into different groups. Write your list in the space below.

2. Share your list of characteristics with your group.

3. Modify your list as needed to include characteristics that you may have overlooked.

4. Work with your group to decide how you could classify the rocks into three different groups based on their characteristics.

5. Write the names you would use to classify each group of rocks.

 

Group 1: ______________________________

Group 2: ______________________________

Group 3: ______________________________

 

6. State the reasons why your group classified the rocks as you did.

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Activity 2:

7. Preview pages 146 – 149 in Prentice Hall Science Explorer: Inside Earth.

8. Read pages 146 – 149 in Prentice Hall Science Explorer: Inside Earth. As you read, complete the outline, “Classifying Rocks.”

9. Review the list of rock characteristics you and your group made in Activity 1. Describe the accuracy of your characteristics to the actual characteristics that are used to classify rocks.

10. Provide examples from the text to support your response.

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Analysis

Study the two rock samples provided by your teacher and explain how scientists would use their characteristics to distinguish between the two different rocks.

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Fossil Fact: CLASSIFYING ROCKS

Provide two examples of how rocks can provide information about Earth’s past. Use information from today’s investigation to support your response.

 

 

IF ROCKS COULD TALK Teacher Resource

 

Background Information: 

Student Materials (per group):

sedimentary rock samples

igneous rock samples

metamorphic rock samples

hand lens

 

In this investigation, students will discover the characteristics that scientists use to classify rocks. In Activity 1, students should be given a variety of different rock samples representative of each rock group. Students should not know the names of the rocks; however, the samples should be large with a variety of characteristics that can be used to distinguish among the rocks. Students will work cooperatively in Activity 1 to predict the different rock groups based on similar characteristics. Possible rock samples that work well for this investigation are as follows:

 

Sedimentary Rocks	Metamorphic Rocks	Igneous Rocks
Limestone with fossil evidence if possible Sandstone Coquina Conglomerate or Breccia	Marble Shale Diorite Gabbro Schist Gneiss	Obsidian Pumice Granite Basalt

 

For the Analysis, students will need to be given two specific rock samples by the teacher. These samples should be different enough in their characteristics that students can draw conclusions about scientists would use their characteristics to distinguish between the two rock samples. Appropriate samples might be: gneiss and obsidian; sandstone and granite; conglomerate and pumice.

 

Answer Cues for Key Question

• Scientists would look at specific characteristics such as grain size, grain shape and texture. For example, obsidian appears to have no grains and is smooth and glassy where as gneiss has large grains or and is banded.

• They may also look at the types of minerals that are found in each rock type.

• Scientists could also determine the origins of the rock based on what the rock contains. For example, coquina might be sedimentary because it contains fossils of animals.