Make-a-Fake – Sedimentary Rocks Name________________

1. Introduction- In this lab you will make a sedimentation tube and some “fake rocks” to help you understand how this earth of ours works. You will investigate how sedimentary rocks form in nature and learn more about sediments and cementation. Use what you learn in this lab, plus your textbook and your lecture/discussion notes, to help you fill in the lab table and answer the homework questions.

Day 1

I. Get a length of tubing and 2 rubber stoppers and build a sedimentation tube as follows:

1. Push and twist one of the rubber stoppers firmly into one end of the tube.

2. Put about 1 inch of gravel in the tube followed by 1 inch of sand and finally 1 inch of clay.

3. Add water until the tube is ¾ full.

4. Stopper the tube by pushing and twisting the second rubber stopper in the open end.

5. Shake and swirl the tube so that all the clasts are stirred up.

6. Stop shaking, hold the tube upright and wait until everything stops moving. Then record your observations below.

7. Allow the tube to remain overnight in the upright position and then add to your observations.

Observations-

II. Make your “fake rocks” as follows:

1. Cover your work area with newspaper.

2. Get 6 cups, a stirring rod and a wax marker.

3. To one cup add about 1cm of dry powdered clay.

4. Add water and stir, adding water bit by bit until your mixture has the consistency of pudding. Be sure to stir to the bottom of the cup so that all the clay gets scooped up.

5. Gently tap the cup against the table to knock the air bubbles out of the mixture.

6. Using the wax marker, label the cup with your initials and what you put in the cup.

7. Using your second cup, repeat steps 4-6 but instead of using clay use about 1 cm of sand and 1cm of dry plaster. Again, add water slowly to get that pudding-like consistency and be sure to include the ingredients on your label.

8. Repeat steps 4-6 using about 1cm of gravel and 1cm of dry plaster with water.

9. Repeat steps 4-6 using just 1cm of dry plaster with water.

10. For your other 2 cups mix up your own choice of ingredients, again using steps 4-6.

11. Set your 6 cups aside in the designated area and allow them to dry and cure.

12. Clean off your stirring rod using a wet towel. Clean up your work area.

Day 2

I. Once your cups have all cured and dried up proceed as follows:

1. Cover your work area with newspapers.

2. Tear open each cup to get your rock out. Keep the label with each rock for future reference.

3. Try to break open each of your rocks using just your hands.

4. Have your teacher break open the tough rocks.

5. Decide what natural rock each of your fake rocks represents and fill in the “Rock Name” row of the data table.

6. Finish the “Ingredients” row of the data table.

7. Bring your data table to me to check it out.

8. Using your notes and your text, fill in the rest of the data table.

Homework

Answer each of the following in the space provided using complete sentences.

1. Explain in which varieties of sedimentary rocks you would most likely find fossils and explain why.

2. Sedimentary rock layers in Earth’s crust often show bedding. What is bedding and how does it form?

3. Name 2 things all of your fake rocks have in common.

4. You used plaster of Paris for your cementing agent. Name some cementing agents Mother Nature uses.

5. Define these words: sediment, sedimentation, and clast.

6. Suppose you travel to the mountains and find a cliff made out of sedimentary rocks. You notice there is several feet of conglomerate that makes up the bottom of the cliff, then several feet of sandstone and finally several feet of shale making up the top portion of the cliff. What do you conclude about how this mass of rock formed?

7. Using rocks you can find around your yard, on the gravel roads, along the railroad tracks, or anyplace you can think of, find what you think are examples of rocks number 1, 2, 3, and 4 and bring them to class.