Ohio Students work in cooperative groups to investigate the effects of water on a broken block of salt. Inquiry variables could include, water temperature, pH of water, investigation of color additives, etc. Limestone caverns are some of the most spectacular caves in the world. These remarkable structures are the result of thousands of years of dissolution of limestone rocks.
Water falls to the earth and absorbs carbon dioxide from the air and soil.
This carbon dioxide undergoes a chemical reaction with the water molecules and forms a weak acid called carbonic acid. Over time, these small channels begin to widen and form huge rooms. Often these rooms are the homes of beautiful formations of rock which were caused as water which has dissolved limestone somewhere else redeposits the material in new places. The procedure is fairly simple and involves cracking a salt block and allowing it to set under flowing water to see the results of dissolution of the salt. The students should hit the salt block with a hammer to crack the block.