Almost everything that is left outside for a long time is worn down and changes occur in the way it looks. This is called weathering. Water and wind can even wear down rocks over a long period of time. You can see an example of this by looking at the round, smooth rocks found in rivers or streams. They were probably once much rougher looking.
This arch was formed over a long period of time by wind or water moving against it.
Sometimes
rocks can be broken down by plants. If a rock has a small crack in it, the
plant can force its roots into the crack pushing it apart. Try It!
Materials:
- One wooden block
- Three hard candies
- Three M & M® candies
- One pair of safety glasses
- Hammer
- Two small clear plastic cups
Procedures:
- Put on the safety glasses. Place one hard candy on the wooden block, and hit is gently with a hammer. Follow the same steps with one M&M®. You will notice that just like igneous rocks, different kinds of candy break down in different ways. Record what happened in a science journal.
- Place one hard candy and one M&M® in the freezer for at least 15 minutes. After they are frozen hit each candy with a hammer before they warm up. What happened? Record what happened in a science journal.
- Put one M&M® in a clear plastic cup and one hard candy in another cup. Add enough water to the cup to cover the candy. Swirl the candy around for 5 to 10 minutes. What happens to the candy? Record your findings in a science journal.
- Place the cups of candy and water in a safe place where you can watch as the water evaporates. Once the water has evaporated record your findings in your science journal. What is left at the bottom of the cup represents a sedimentary rock that has been changed by weathering.
Or
Take a plastic bottle of water and place it in a freezer. Come back later, after it has frozen, and look at the bottle. What happened to the shape of the bottle? When water freezes, it takes up more space, or expands. If the bottle was filled to the top and the lid was on tight, the ice forced the bottle to expand. When the weather outside changes to freezing cold, the water located in the cracks of rocks can force the rocks apart as it changes to ice.
|
|||||
| Get the plug-ins: Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information: the title of the activity, the URL (Internet address), and your name. Remember that no pictures can be used which show any student faces or has a student name. Updated
August 18, 2005
by: Glen Westbroek |
