Introduce this basic chemistry experiment to your participating children by explaining to them the basic relationship between acids and calcium. In particular, explain to your youngsters how an everyday acid, such as vinegar, over time will break down the molecular bonds of calcium, such as an eggshell. Furthermore, you should also capitalize on this opportunity to extend health and safety knowledge to your young scientists by instructing your scientists to wear white laboratory coats, safety goggles and rubber gloves throughout the practical.
Ask your young scientists to write down a couple of sentences as a prediction for this experiment. For example, your young scientists could write that they expect the eggshell to be dissolved by the vinegar, which will leave just the internal membrane of the egg. Your kids may use more basic terminology to explain the prediction made, known as a hypothesis, but you should look for sound reasoning and justification for whatever outcome your children predict.
Place five eggs inside a zip-top freezer bag before adding enough pure vinegar to fully submerge all of the eggs, such as 5 cups. Allow your youngsters to view the experiment setup, take photographs and draw pictures of the design before carefully placing the bag inside a deep sink or other waterproof area. Leave this bag for at least three whole days to ensure the vinegar has completely consumed the eggshell.
The best way to demonstrate the changes in the egg is to remove eggs from the zip-top bag, wash them off with a light dribble from the faucet before allowing your children to handle the eggs themselves. The eggs are quite durable and resilient at this stage, but you should ensure that your young scientists lay down some newspaper or handle eggs in a sink, as the eggs can still be punctured and cause a real mess. As your youngsters play with the rubbery, bouncy eggs, reinforce the message that the acid of the vinegar has dissolved the calcium of the eggshell.