Materials: Vinegar 2 glasses A piece of chalk (it is made of limestone) Several different rock types and minerals A magnifying glass
Instructions: - Pour a glass of vinegar into a glass. - Add a small piece of chalk (it is made of limestone). - Watch closely. After a few minutes, the piece of chalk starts to fizz. - Put another glass of vinegar into the other glass. - Put some different rock types and minerals into that glass (some of them contain limestone). - Watch closely. After a few minutes, some of them start to fizz and we can see bubbles.
WHY? Because vinegar is an acid and it dissolves small particles of calcium carbonate in the limestone (a mineral). We can see bubbles, because it releases carbon dioxide, a gas that rises to the surface. Rocks or minerals that contain calcium carbonate fizz. Those that don’t contain calcium carbonate won’t fizz.