Dr. V Show: Naked Eggs
Things you will need:
- Raw egg
- Tall glass
Place the egg in the glass and pour enough vinegar to cover the egg. Watch the egg closely. What do you see happening? Leave the egg in the vinegar for a full day. What does the egg look and feel like now? Carefully change out the vinegar with new vinegar, again, enough to cover the egg and leave the egg in the glass for a week. Check on it each day and see what changes are happening. At the end of the week, pour out the vinegar, being careful not to drop your egg. Rinse the egg carefully with water. What does it look like? What does it feel like?
How does it work?
Egg shells are made of calcium carbonate. Vinegar is acetic acid. The vinegar you get from the grocery store contains about five percent acetic acid and 95 percent water. The vinegar reacts with the calcium carbonate by breaking it down into parts, calcium and carbonate. You can see the calcium, the stuff floating around in the vinegar, and the carbonate is the carbon dioxide bubbles you see coming off the egg shell. Eventually all of the calcium carbonate reacts with the vinegar and you have a naked egg!
Another thing to notice is that your egg may look bigger than the other eggs still in the shell. After the shell is gone, some of the vinegar begins to get into the egg's membrane (the thin sheet that's holding the egg white and yolk together), causing the egg to get bigger. This flow of vinegar into the membrane of the egg is called osmosis, when liquid from a higher concentration flows through a membrane into a less concentrated solution. You may even be able to squeeze the egg quite a bit, carefully.