It’s that time of year again! With egg-dyeing, hiding and hunting eggs are in the limelight. Why not combine the festivities with some science?
Make an egg shell disappear
What You Need:
What You Do:
- Place the raw egg in the container.
- Cover it with vinegar.
- Leave it undisturbed for two days.
- Take the egg out and rinse.
- What do you notice?
What’s Going On?
Eggshells are made with calcium. It’s the hard mineral that gives the eggshell rigidity. Vinegar is an acid and it dissolves calcium. When the egg sits in a vinegar bath, you can see the reaction right away. Little bubbles appear on the surface of the egg. Eventually the whole hard part of the eggshell dissolves leaving the tough iner membrane to hold the contents of the egg.
Take it Further
Use your shell-less egg for the next experiments.
Shrink the Egg
Place the shell-less egg in a container and cover it with corn syrup. Leave it for a few hours. What do you notice?
The egg shrinks because there is less water in the corn syrup and more water inside the egg. Water wants to move where it is less crowded with water molecules. This is called diffusion. It travels across the membrane (this is called osmosis) to the syrupy solution. The result is a smaller egg with less water in it.
Grow the Egg
Take the egg from the sugar syrup and rinse it. Place it in a container and cover it with water. You can even add food coloring. Wait a few hours. What do you see?
There are fewer water molecules inside the egg now, than the surrounding water so water moves across the membrane into the egg and makes it swell.
If you’ve added color, the color moves across with the water and the inside of you egg is colored now.
Erupt the Egg
Poke a hole in the egg with a toothpick and the water pressure inside makes it erupt out.