What You Need:
Question: How can ice break up rock?
1. First, fill a balloon with water and tie off the end.
2. Then, cover the water-filled balloon with play dough.
3. Put the covered balloon in the freezer over night.
4. Check out the balloon the next morning.
5. Can you explain what happened to the play dough?
A Scientific Explanation
Water is sometimes trapped in the cracks of a rock. When this water freezes, it expands, or gets bigger, and causes the cracks to widen. After a while, this freezing and expanding will break up the rock into smaller and smaller pieces until all that's left is dirt. This never-ending process is known as erosion.
Look for examples of erosion in your area. A good place to observe erosion is where a highway cuts into the side of a hill or mountain. Look for signs of erosion, such as cracks in the rock surface or pieces of smaller rocks at the base of the hill or mountain.