Acid in the Rain Causes Erosion

New rocks constantly form inside the Earth and get pushed up by earthquakes, volcanoes, and the constant shifting of tectonic plates. Erosion is the natural process that wears down these rocks, constantly changing the face of planet Earth. Erosion and mountain building have gone on since the Earth was born.
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.
Materials:

Lemon juice

Vinegar

Three pieces of regular white chalk

Place one piece of chalk in a glass of lemon juice.

Note: for each glass, the chalk should be about three-fourths submerged in the liquid.

Place the other piece of chalk in a glass of vinegar.

Place the last piece in a glass of plain tap water.

Check back on the glasses over the next three or four days.
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 an effect similar to the vinegar or lemon juice’s effect on the chalk and acidic rainwater can eat away at rocks causing them to erode.

Nye Labs, http://nyelabs.kcts.org/openNyeLabs.html