When carbon dioxide in the atmosphere dissolves into raindrops, it causes the rain to become naturally acidic. This kind of natural acid rain can dissolve and erode rocks. Here’s an experiment to see how chemical erosion works.
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SOL: Science:
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Objective:
Materials:
lemon juice
vinegar
3 pieces of regular white chalk
Procedure:
Place one piece of chalk in a glass of lemon juice (the chalk should be about 3/4 submerged)
Place one other piece of chalk in a glass of vinegar
Place the last piece in a glass of plain tap water
Check the chalk every day for four days
How did the chalk change?
Why?
Lemon juice and vinegar are acids. Chalk is made of rock called limestone, which contains a chemical called calcium carbonate (CaCO3). Acids react quickly with the limestone, breaking apart the calcium and the carbonate to form calcium (Ca) and carbon dioxide gas (CO2).
Acid rain is much weaker than vinegar or lemon juice. Nevertheless, as acid rain falls, it has a similar effect to the vinegar or lemon juice’s effect on the chalk. Acidic rain water can eat away at rocks, causing them to erode.