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Grades 5 – 8 "Dissolution Experiment"
Materials
- white vinegar
- shallow pan
- eye droppers
- samples of rocks, one of which is limestone.
Procedure
- Explain that it is sometimes possible to tell what minerals rocks are composed of by their physical properties such as appearance, grain size, hardness, texture, color, and whether they can be dissolved.
- Remind the students of the dissolution process of limestone explained in "Background Information." Explain that vinegar is an acid stronger than carbonic acid, but weaker than sulfuric acid.
- Place the rock samples in the shallow pan. Using the eye dropper, start coating the rocks with the vinegar. This is known as the "Bubble Test." The limestone piece will bubble as it dissolves while the other rock(s) will not. (This is a vivid demonstration, be prepared to allow each student enough time to try it).
- Ask the students to identify which rock is limestone.
Grades 9 – 12 "Dissolution Experiment"
Materials
- two beakers
- 20% solution of hydrochloric acid (also known as muriatic acid)
- a sample of limestone
- a sample of non-carbonate rock
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