BOUNCE A RAW EGG. THEN TURN IT BLUE AND BOUNCE IT SOME MORE!
This activity has been done in every science classroom in the country, but that is because it is SO COOL. And you can do it right in your own kitchen just in time for Easter with materials you already have in your fridge and pantry. Everyone in the family will love experimenting with ‘the bouncing egg’ and you will never look at Easter egg decorating the same again!
LEARN SCIENCE VOCABULARY:
Yolk – the yellow part inside the egg. It is there to feed a growing embryo IF the egg was fertilized (eggs from the grocery store are NOT fertilized and cannot hatch into a chick!).
Membrane – the very thin covering under the shell of an egg. Our skin is also a membrane, and there are also thinner membranes lining our internal organs.
Osmosis – the process of a liquid (like water) moving through a membrane to create equal concentrations of materials on both sides.
- Eggs (brown eggs are fun to use because the darker color of the shell helps you see it as it comes off)
- White vinegar
- Cups (just large enough for your egg)
- Food coloring
- Corn Syrup (optional)
HOW TO MAKE IT: (Don’t be too shocked at how easy this is to do…)
- Place an egg in a cup and pour vinegar to just cover the egg. (You will probably want to do 2 or more eggs so you have plenty to experiment with!). You should immediately start seeing bubbles coming off the shell – this is the Carbon Dioxide being released in the chemical reaction as the vinegar breaks down the egg shell.
- Let the egg sit for about 48 hours (or longer…some say to change the vinegar after a day, but I was too busy to remember that and the eggs turned out fine anyway!) Have the kids check it periodically and make observations (use senses of sight, smell and touch) about what is happening to the egg. What do they think will happen to the egg when all of the shell is removed?
- After 48 hours or so, carefully remove the egg from the vinegar with a slotted spoon.
- Rinse it under warm water, gently rubbing the surface to remove the rest of the shell covering. Kids can definitely help with this part. (The naked egg is a lot sturdier than you would think…but if they squeeze it too hard, it will burst!)
- Get out a brownie pan or something similar (so your naked egg doesn’t roll onto the floor) and hold the egg about 3-4 inches above the pan. Drop it and watch it bounce!
- Have kids make observations about the egg and the MEMBRANE that holds it together. You will also be able to see the YOLK fairly clearly inside, especially if you hold the egg up to a light.
You can color your naked eggs by placing them into a cup of water tinted with food coloring. After about 6 hours take your eggs out and see their vibrant colors! The colored water has actually permeated through the egg MEMBRANE through the process of OSMOSIS, coloring the inside of the egg as well.
If you want to keep going with this awesome activity, put your naked and colorful eggs into a cup and cover them with corn syrup. Let them sit overnight and observe what happens!
The water from inside the egg has moved out into the cup through the process of OSMOSIS. You will be able to see the water floating on top of the corn syrup in the cup.
AND THEN… you can turn them back into big rubbery eggs by soaking them in water again! The fun seriously never ends with this one.
THE SCIENCE BEHIND IT:
Removing the Shell: Vinegar (a.k.a. acetic acid if you want to get science-y) breaks down the eggshell (made of a material called calcium carbonate) through a chemical reaction that releases Carbon Dioxide gas (which you can see in the form of bubbles coming off the egg as soon as it hits the vinegar). This is very similar to how acidic food and drinks can break down tooth enamel over time! [Check out Bubbly Designs: a baking soda and vinegar activity if you want to learn more about chemical reactions with vinegar.].
Coloring, Growing, and Shrinking the Egg: The egg will get bigger and absorb color as it soaks in the cup of colored water because some of the water from the vinegar is moving into the egg through the its MEMBRANE (this is called OSMOSIS). Water will move in or out of a MEMBRANE in order to equalize the concentrations of salts and other materials on both sides of that MEMBRANE. Because corn syrup has a high concentration of these materials, the water from inside the egg moves out of the MEMBRANE and into the cup of corn syrup, causing the egg to appear shrunken and wrinkly! When you put it back in a cup of clear water, OSMOSIS works the other way and water moves back into the egg.