I thought it might be fun to throw in a few Easter Egg Experiments this week to go along with the Easter Crafts that were in our last issue.

Even if you "don't do Easter," you'll still be able to do these fun experiments with your kids... and they may even learn a little too!

Enjoy and Happy Easter!

Egg Etching

Most children decorate eggs for Easter, but here's a way to get in a little science experiment with your decorating. Is it possible to actually etch an egg without breaking it? We have found the answer.

What You'll Need:

• Hard Boiled Egg
• Crayons
• Widemouth Jar
• White Vinegar

What to Do:

1. Draw on your egg with the crayons. You create designs, write words, or even just scribble. The color of the crayons doesn't matter. Be very careful not to crack the egg when you are writing on it.

2. Put the egg into the widemouth jar and cover it with white vinegar.

3. Let the egg stand in the vinegar for two hours and then pour out the vinegar and replace it with fresh vinegar.

4. Let the egg stand in the fresh vinegar for another two hours, then take it out of the jar. Wash the egg and remove all the crayon markes. This will create an etched egg shell.

Why This Works

The crayon acts as a protective barrier to the vinegar. The acid in the vinegar dissolves much of the calcium carbonate of the eggshell. The wax in the crayons protects the parts of the shell that you wrote on and keeps it from dissolving.

NOTE: Sorry about the less than optimal picture for this experiment. I tried to photograph the eggs that we created, but the camera wouldn't pick up the etching well enough to show them here. Hopefully the drawing here will give you an idea what to expect.

Which One Is Cooked?

What You'll Need:

• 1 Hard Boiled Egg (cooled to the same temperature at the raw eggs)
• 2 Raw Eggs

The Experiment

Present the child with the eggs and ask them to tell you which one is the hard boiled egg and which ones are the raw eggs without breaking them. Let them examine the eggs until they either make a guess or give up, and then tell them that there is a secret method to detecting the cooked egg.

Lay each egg down on a flat surface and spin them long ways like a top. Try to get them all spinning at the same time if you can, then ask the child which one is different.

The two raw eggs wobble. The hard boiled egg spins.

Touch each of the eggs lightly as it's spinning.

The two raw eggs will start moving again after you've tried to stop them, but the hard boiled egg will stop spinning completely when you touch it.

The Explanation

When you spin the two raw eggs, the yolks and whites are also moving inside the eggshell. The inertia of spinning causes the inside of the egg to move at a different rate than the outside of the egg because it's mass is different. That's why they wobble and still move even after you've tried to stop them.

The hard boiled egg doesn't wobble because cooking the egg has made the inside of the egg solid and less affected by the enertia. The solid inside of the egg is also closer in mass to the shell, which allows it to spin more smoothly and respond to stopping more quickly.

Egg In A Bottle

Kids never cease to be amazed by this little trick, no matter how many times you show it to them.

What You'll Need

• 1 Hard Boiled Egg Peeled
• Boiling Water
• A Bottle with a neck slightly smaller than the egg

The Experiment

1. Set the egg on the neck of the bottle to demonstrate that the egg simply won't fit in the bottle. Tell the child that you know a trick to make that egg go down into the bottle without breaking it.

2. Remove the egg from the bottle and pour the boiling water into the bottle. Carefully roll the water around in the bottle and then pour it out.

3. Quickly put the egg back on the neck of the bottle and wait for it to get sucked down into the bottle.

The Explanation

When you put the hot water into the bottle and then poured it out, the hot water left steam behind in the bottle. The steam forces out some of the air that was already in the bottle. As the steam in the bottle cools down, it converts into tiny droplets of water. The drops of water require less space and this reduces the amount of air pressure in the bottle. The pressure on the outside of the bottle is greater than the pressure on the inside of the bottle and that is what forces the egg into the bottle.

You can remove the egg from the bottle using the same process in reverse. Hold the bottle upside down and blow into the bottle for about 30 seconds. Be sure to seal your lips around the mouth of the bottle when you do this. By blowing into the bottle, you will increase the pressure on the inside of the bottle and force the egg out.

Can You Make An Egg Float?

This experiment will be too difficult for younger kids to grasp, but school age children should be able to do this one. The idea is to demonstrate bouyancy and how the density of water affects it.

What You'll Need

• 3 Clear Drinking Glasses (identical ones are best)
• 3 Eggs
• A Tablespoon
• A Straw, popsicle stick, or stir stick
• Water
• Salt

The Experiment

1. Fill each of the glasses halfway up with water. Put one egg in each glass. Choose one of the glasses to be the control glass (Glass 1). That means that you won't do anything to it and it will give the child something to compare the other glass to.

2. Now, begin adding salt to the non-control glasses (Glass 2). Start by adding 3 tablespoons of salt to one of the glasses and gently mixing it up in the water with a stir stick. Observe what happens with the child.

3. Add 10 tablespoons of salt to the other non-control glass (Glass 3) and gently stir it up. Slowly pour water into the glass until it is full, but don't stir it.

What You Should Observe

Glass 1: This glass simulates a fresh water environment. The egg will sink to the bottom in fresh water.

Glass 2: This glass simulates a salt water environment. The egg should rise to the top of the water and float in this glass.

Glass 3: This glass shows what happens when you add fresh water to salty water. The egg should be suspended in the middle.

The Explanation

The more dense a liquid is, the greater it's bouyancy and the easier it is to float. Salt makes water more dense.

When you add fresh water to the denser salt water, it will float also. In fact you can tell exactly where the salt water and the fresh water meet in the glass by where the egg is floating.

How Strong Is An Eggshell?

Usually we think of eggshells as being pretty fragile, but this experiment shows that they are much stronger than we think.

What You'll Need

• 4 Eggshells
• Masking Tape
• Scissors
• Weights (Books, cans, or anything else that you can stack)

The Experiment

1. Wrap a piece of masking tape around the middle of each of your eggshells. Cut them in half with the scissors on the masking tape. The tape will keep the shells from cracking and let you get a flat edge on each of the shells. You'll need four halves.

2. Lay each of the four halves down on a table with the cut side down and the domed side up. Put them close together to make a square.

3. Start laying on the weights. We've done this experiment with both canned food cans and books. The easiest way we've found is to put a small book on first and then add other things on top of the book. My kids like using wooded blocks the best.

4. Keep stacking on the weights until one of the eggshells begins to crack... This can be quite exciting to the kids. Be sure to note how much weight the eggs hold - the kids will be impressed.

The Explanation

The real secret to the strength of the eggshells is their shape. Because each shell is domed, there is no single point on the shell that has to support all the weight and the weight is carried down the curved walls to the base of the shell (the flat edge). This makes them extremely strong.

Talk with your child about how to apply this idea to building construction and other elements in real life. You can also talk about other shapes that use the same basic principle to increase strength.