This lesson developed by Michelle M.
Recommended Ages: Preschool and Early Elementary
What You Need
- 3 raw eggs
- 3 clear drinking glasses or beakers
- Measuring cup
What You Do
- Put an egg in the bottom of each glass or beaker.
- Pour vinegar into the measuring cup.
- Pour the vinegar from the measuring cup into the glasses until the eggs are completely covered by vinegar.
- Watch the eggs for 3 or 4 days.
What Is Happening
You may see little bubbles come off of the eggs. The color of the eggshells may change as well as the texture. On day 3 or 4, carefully pour of the vinegar into a sink. Now, gently remove the eggs from the glasses or beakers. Feel them. Carefully squeeze them. The hard eggshells have totally changed into a soft and rubbery material.
Eggshells are made of lots of calcium. The calcium makes the shells hard. Vinegar has what we call acid in it. Acid breaks down and eventually dissolves the calcium in the eggshells. Over time, the shells become soft and rubbery feeling. We need calcium in our diets everyday for our bones to stay nice and dense and hard. When people don't get enough calcium in their diet, their bones become brittle and break more easily. Sometimes people can tell they need calcium when they find their nails get soft, too. [ You need sunshine and the atoms found in green vegetables boron, magnesium in order for your body to use the calcium. ]
To see that bones are made up of calcium, you can get some chicken bones and put them into a glass of vinegar for a few days. What you will find is similar to the eggs, you have rubbery and soft chicken bones! So, to keep your bones hard and strong, get lots of calcium from drinking milk and eating dairy products! [ If you don't have a milk allergy. ]