Earth Science Week Classroom Activities

Frozen Power

Activity Source:

Source: Geological Society of America.

Written by Greg McNamara, Christine V. McLelland, Gary B. Lewis, Davida Buehler, and Yueyi Che.
Adapted with permission.

You may be familiar with ice cubes in your favorite soda, but do you know there are very big ice cubes (scientists call them glaciers) hundreds to thousands of meters thick, lying in places
with high mountains? These glaciers shaped beautiful landscapes all around the world — from Glacier National Park to Yosemite, from Patagonia in South America to the Himalayas in Asia.

If you go camping in the mountains, you likely will find it cold at night. It’s been said that if some water gets into the cracks in boulders and freezes and thaws in cycles, the water may shatter the rock into small pieces. Is this true? Is ice really so powerful that by freezing it can force the rock to break? Let’s experiment to find out!

Materials

• Clear plastic containers or bottles with push-on lids (or you can use scissors to cut out a flat plastic lid yourself )
• Mud
• Water
• Duct tape
• Measuring tape/ruler
• Freezer
• Notebook and pen or pencil

Procedure

1. Before you conduct this experiment, read through the procedure. Make a prediction about the outcome and write it down in your notebook!
2. Fill one container with water until overflowing. Push on the lid so that there is no air inside.
3. Fill another container with thick mud. Push on the lid so that there is no air inside.
4. Fill another container with water until overflowing. Push on the lid so that there is no air inside. This time, tape the lid.
5. Fill another container with thick mud. Push on the lid so that there is no air inside. Tape the lid.
6. Measure the size of each container with your measuring tape and write down the sizes in your notebook.
7. Place the four containers in the freezer and leave them overnight.
8. After the water and mud are frozen, take them out from the freezer carefully and make some observations:
• Is the push-on lid still in place on all four containers?
• Is the container the same shape for all four containers?
• Did the tape seal break?
• What were the size measurements before and after the containers were frozen?
9. Write in your notebook about each container’s outcome, whether it agreed with your prediction, and whether the outcome was the same with water and mud.
10. After your experiment, think about these questions:
• When water freezes into ice, it does what?
• Is it possible for water in a rock crack to freeze and break the rock?