Naked Egg Science Experiment – Steve Spangler Science

Which came first, the rubber egg or the rubber chicken?

Naked Eggs Experiment — Steve Spangler Science 

Which came first, the rubber egg or the rubber chicken? Find out in this egg science experiment. Vinegar is used in this easy-to-perform naked and bouncy egg experiment that kids can’t stop talking about! 

This experiment answers the age-old question: Which came first, the rubber egg or the rubber chicken? It’s easy to make a rubber, or a “naked,” egg if you understand the chemistry of removing that hard eggshell. What you’re left with is a totally embarrassed, naked egg and a cool piece of science. Learn how to make a bouncy egg (a.k.a. a naked egg) in this egg in vinegar experiment that you can easily do at home, at school or in your STEM science club. 

All you need are a few eggs straight out of your refrigerator and some regular household vinegar (ask your parents about what’s available in your home and be sure to get permission to use it!) and you’re well on your way to the best egg experiment online. 

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Experiment Materials

  • Raw eggs
  • Large glass or container
  • Vinegar
  • Patience
  • Adult supervision

Experiment Videos

Experiment

1

Place the egg in a tall glass or jar and cover the egg with vinegar.

2

Look closely at the egg. There will likely be tiny bubbles forming on the shell.

3

Leave the egg in the vinegar for a full 24 hours.

4

Change the vinegar on the second day. Carefully pour the old vinegar down the drain and cover the egg with fresh vinegar. Place the glass with the vinegar and egg in a safe place for a week—that’s right, 7 days! Don’t disturb the egg but pay close attention to the bubbles forming on the surface of the shell (or what’s left of it).

5

One week later, pour off the vinegar and carefully rinse the egg with water. The egg looks translucent because the shell is gone! The only thing that remains is a delicate membrane of the egg surrounding the white and the yolk. You’ve successfully made an egg without a shell. Okay, you didn’t really make the egg (the chicken made the egg), you just stripped away the chemical that gives the shell its strength.

How Does It Work

Let’s start with the bubbles you saw forming on the shell in this egg in vinegar experiment. 

The bubbles are carbon dioxide (CO2). Vinegar is an acid called “acetic acid” (CH3COOH); white vinegar from the grocery store is usually about 4% acetic acid and 96% water. Eggshells are made up of calcium carbonate (CaCO3). The acetic acid in the vinegar reacts with the calcium carbonate in the eggshell; the calcium acetate plus water and carbon dioxide combine and form bubbles on the surface of the shell.

The chemical reaction looks like this:

2 CH3COOH + CaCO3 = Ca (CH3COO)2 + H2O + CO2
Acetic acid + Calcium carbonate = Calcium acetate + Water + Carbon dioxide

The egg looks translucent when you shine a flashlight through it because the hard outside shell is gone. The only part that remains is the thin membrane called a “semipermeable membrane.”

You might have noticed that the egg got a little bigger after soaking the egg in the vinegar during this egg science experiment. Here’s what happened: Some of the water in the vinegar solution (remember that household vinegar is 96% water) traveled through the egg’s membrane in an effort to equalize the concentration of water on both sides of the membrane. This flow of water through a semipermeable membrane is called “osmosis.”

If you take your naked egg and place it in a glass filled with corn syrup, the egg will shrivel. Since corn syrup has a lower concentration of water than the egg does, the water in the egg moves through the membrane and into the corn syrup to equalize the water concentration levels on both sides.

Take It Further

Change a Variable

Do organic or free-range eggs have an eggshell that is stronger or weaker than generic, store-bought eggs? What about really fresh eggs compared to those that have been around for a while? Conduct your own egg in vinegar experiments on several different kinds of eggs all at once to observe any differences in the time required for the vinegar to dissolve the shells.

Another variation in this egg in vinegar experiment is to try using concentrated vinegar instead of traditional vinegar. Concentrated vinegar is about four times the strength of traditional household vinegar. If you really want to cut down on the time it takes for the eggshell to disappear and you are a chemistry teacher, try using with 1 molar hydrochloric acid. But be careful — this is really strong stuff!

The Bouncy Egg Experiment 

Wondering how to make a bouncy egg? Here’s another egg experiment idea: Put an egg in a separate glass. Then, cover the egg with vinegar. Allow the egg to sit in the vinegar for 24 hours. After 24 hours, pour out the vinegar and take the egg out of the glass. Drop the egg into the sink from a height of 3 inches. What happens? Continue dropping the egg from different heights (all drops should be done over the sink). What is the greatest height that you can drop the egg from before the egg goes splat? Can you measure the height of the bounces? 

Secret Message Egg Experiment

You’ll totally freak someone out by making a message “magically” appear on an egg! Start by boiling an egg in a saucepan on the stove for 10 minutes. Remove the egg from the pan and let it cool. Use a crayon or a small candle to write on the eggshell. Write anything you want: your name, a design, a symbol — just like you were going to make wax designs on an Easter egg. 

Next, place the egg in a glass filled with vinegar. Bubbles will begin to form on the surface of the egg. When the bubbling stops, pour out the vinegar and cover the egg with fresh vinegar. Once the second round of bubbling has stopped, remove the egg from the glass of vinegar and rinse it off with cool water. Rub your fingers over the surface of the egg. What do you feel? The eggshell is gone, but you should be able to decipher what you wrote or drew on the eggshell. Wax does not react with acid (vinegar). For that reason, the eggshell remains intact underneath your wax design, revealing your words or artwork.

Safety Information

WARNING! IMPORTANT SAFETY RULES
When performing this egg in vinegar experiment, always remember to wash your hands well with soap and water after handling raw eggs. Some raw eggs may contain salmonella bacteria that can make you really sick!

Steve Spangler Science

Love this egg experiment? Can’t get enough of our bouncy egg experiment? There’s more where that came from! Check out the HUGE Steve Spangler Science online library of super fun science experiments for kids. Don’t miss our top five most popular science experiments. Looking for all-in-one science kits? We have a fantastic selection of science-themed experiments, toys and products that will keep those inquisitive minds working. From chemistry and physics to biology, there’s always some amazing to science to learn at Steve Spangler Science.

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