Craft Time: 2 Eggs-ellent Experiments

This time of year whenever anyone hears “eggs” they automatically throw “Easter” in front of it. But for at home mad scientists in the Valley, we add “periment” to the end of it. Get it? Eggs-periment.

Anyway, if you’re looking for something a little more educational (and just plain cooler) to do with your kids, besides the normal egg dying fiesta, try out these delightful experiments ­– oops, eggspiriments:

Rubber Eggs

Materials

• Raw Egg
• Vinegar
• A container
• Also: you can add food coloring if desired to make a brightly colored egg)

Procedure

1. Put your egg into the container

2. Pour vinegar into the container until the egg is covered

3. Put the glass aside where it will not be disturbed but be sure to make some observations! You’ll likely see some bubbles are forming.

4. Let the egg soak overnight.

5. Rinse the vinegar and any residue out with water and then cover the egg again with fresh vinegar

6. Wait for 3-6 days. (the longer it sits, the more durable it will be)

7. Rinse off the egg and examine the changes in texture, shape, etc. And if you’re feeling lucky, give it a bounce from a few inches off a surface!

How’s it work?

An eggshell is made of calcium carbonate. That’s a complex arrangement of carbons, calcium, and oxygen. Vinegar is made of acetic acid. The little bubbles you see in the water are made of carbon dioxide gas; just like the bubbles you see when you mix baking soda and vinegar.

Once the shell has dissolved, the vinegar will cross over the semi-permeable membrane through a process called osmosis, causing the egg to become “hardened” and rubbery.

What does one do with a rubber egg after all the observations are complete? Keep experimenting of course! 


Amazing Changing Egg

Materials

• 2 rubber eggs
• Karo syrup
• Water
• Containers

Procedure

1. Fill a container with water and place one rubber egg inside.

2. Fill one container with Karo syrup and place the other rubber egg inside.

3. Allow the eggs to soak for 24 hours.

4. Pull the eggs out of the glasses and observe what has happened. Notice how much larger the egg in the water is than the egg in the sugar solution.

How’s it work?

Karo syrup has a very high density that comes from a high concentration of dissolved sugar. These sugar molecules are too large to pass through the semipermeable membrane of the egg, but the water molecules from the egg can. These water molecules pass through the membrane of the egg into the Karo syrup until the concentration of water molecules is the same on both sides. The water movement, from egg to syrup, results in the shrunken egg.

The other egg that you soaked in water grew, but why? Just as the concentration of water molecules is higher in the egg than in the Karo Syrup, the egg has less water concentration than that of the water. In this case, water molecules are moving into the egg, instead of out. The increase in water results in the expansion of the egg.