Make A "Rubber" Egg!

What happens when you drop an egg? It breaks, right? Well, not if you remove the shell first! Here's how to do this...

What you'll need:
1 egg
Vinegar
1 jar with lid
Spoon

This is very simple - put the egg into the jar, then pour vinegar over it to cover. Place the lid on the jar loosely, just to trap the vinegar smell. Look at the egg - what's happening? Soon after adding the vinegar, you'll see small bubbles forming on the eggshell. These are bubbles of carbon dioxide (CO₂) gas. They come from the chemical reaction of the vinegar with the calcium carbonate in the shell. Remember that the formula for calcium carbonate is CaCO3. When you remove CO₂ from CaCO₃, you're left with CaO, or calcium oxide.

But wait - this gets better! Let the egg stay in the vinegar for several days. Eventually, the whole shell will dissolve! The egg will get larger because it absorbs some vinegar, and it will be held together by the proteins that were originally in the shell. The vinegar makes these proteins tougher, and the egg will now feel like a water balloon! Using a spoon, remove it from the jar and hold it in your hand. Hold the egg about an inch above a counter and drop it - you will actually see it bounce! But be very careful when doing this. This "rubber" egg is very delicate, and if it breaks, you will have a small "eggsplosion"!!

Shell Games

Let's start talking about the various parts of an egg from the outside in. The hard outer covering of the common chicken egg is, of course, called the shell. Eggshells contain 95% of the mineral calcium carbonate and 5% of protein. Calcium carbonate (CaCO₃) can also be found in other places - sea shells, pearls, and rocks such as limestone and marble.

In the supermarket, you will see eggs with both white and brown shells. There isn't any difference in the nutrition you get from either color. It's just that some breeds of chickens (such as the Leghorn) lay white eggs, and some (like the Delaware) lay brown eggs. There is actually a kind of South American chicken (the Araucana) that lays blue-green eggs!