Every day, rocks are subjected to wind, rain and other mechanical processes that cause them to breakdown into smaller pieces and different forms. This process of weathering is part of the rock cycle and causes sedimentary, igneous and metamorphic rocks to break down into smaller sediments and soil-sized particles. You can learn a about rock weathering right in your own kitchen! Try this fun experiment to learn more about the mechanical weathering of rocks and post your results in the comments below.
You will need:
- Plastic Wrap
- Hand Magnifier
- Camera (optional)
Step 1: Moisten the clay with a small amount of water. You want the clay to absorb as much water as possible without being dripping wet. Add a small amount of water to the clay and knead it until the water is absorbed, repeating until the clay is saturated.
Step 2: Divide the clay into two equal pieces and roll it into a ball or form into a square.
Step 3: Wrap each piece of clay in plastic wrap.
Step 4: Place one piece of clay into the freezer and leave the other piece on a table or counter. Let the clay stay in the freezer overnight.
Step 5: The next day, remove the clay from the freezer and unwrap both pieces. Place the two balls of clay side-by-side and observe your results. Do the clay pieces look different after one day and then over time? If so, how? Write about your findings in a notebook and take pictures of the results after each day to see how the clay rock changes.
Step 6: Wrap each clay piece back up and put the one piece back into the freezer and repeat for several days. Observe the clay pieces each day and see how the cracks change over time.
The clay from the freezer should have the some cracks. Examine the clay with a hand magnifier to get a closer look at the cracks. The cracks result from the freezing and expanding water just as a rock that has water freeze in holes or existing cracks in the rock. Over time, the freezing and expanding of rainwater will cause a small crack in a rock to become big and allow the rock to split. If the frozen clay does not crack after several days, repeat the experiment with more water in the clay.