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Science Projects for Dissolving Rocks

Weathering is the process of disintegrating rock; the two primary types are chemical and mechanical weathering. Chemical weathering is caused by an agent, such as acid rain, and changes the physical properties of the rock itself. Mechanical weathering results in the rock being broken into pieces and can be caused by factors such as water, wind or ice. Guide your students through science projects that show how rocks can be dissolved.

Chemical Weathering 1
- You will need: two small pieces each of limestone, granite, marble and sandstone; 8 8-ounce cups, a 1-liter bottle of seltzer water, masking tape, a black marker and a watch. Fill half of the cups with seltzer water and half with tap water. Fill each cup about three-quarters full. Put a piece of each type of rock into each type of water. Label the cups with the marker and masking tape according to the rock and water type inside each. Write what you think will happen to the rocks. After 15 minutes, observe any changes in the rocks. Record your observations. Leave the rocks overnight. Observe and record changes the following day. Compare the difference between the types of water and the kinds of rocks.
Chemical Weathering 2
- You will need: three identical pieces of chalk, lemon juice, tap water, vinegar and three small drinking glasses. Fill each glass half-full with a different liquid: water, lemon juice and vinegar. Stand a piece of chalk in each glass so that part of it is submerged and part is outside the liquid. Write your predictions about what will happen to each piece of chalk in your lab notebook. Over the next four days, observe and record the changes in each piece of chalk.
Stream Weathering
- Obtain two handfuls of rock pieces: limestone, shale or sandstone. Put half of the rocks inside a plastic jar. Put the other rocks into a box for later comparison. Fill the jar half-full with water atop the rocks. Put the lid on the jar tightly. Hypothesize what will happen after the rocks are shaken. Shake the jar 1,000 times. Observe changes in the rocks that were shaken. Pour the water out of the jar through a coffee filter. Compare the rocks removed from the jar with the rocks in the box. Compare the results to your hypothesis. Explain how this experiment relates to weathering by streams.
Glacial Weathering
- You will need: five different types of rock, five plastic bottles and tap water. Place each rock into a different plastic bottle. Use a permanent marker to label the bottles according to the type of rock in each. Cover the rocks with water. Place the bottles into a freezer. Predict which type of rock will be changed the most by the freezing process. Once the water is frozen, remove the bottles from the freezer and let the water melt. Place the bottles back in the freezer. Repeat the freezing and thawing process five times. After the fifth thawing, remove each rock from the bottle. Observe the changes in the rocks. How do the results compare to your original hypothesis?

Rocks & Minerals