To practice the steps of the scientific method, students experimented simple chemical reaction demonstration. We poured vinegar over an egg and observed it over several days. They came up with hypotheses of what they thought would happen and recorded their observations.
We learned that the calcium carbonate in the eggshell caused a chemical reaction in the vinegar, causing the shell to be removed. The next day, this is what the egg looked liked:
Students were even able to bounce it!