Learning how to make a rubber egg is a classic science project that kids love. And it’s so easy! Literally all you need to do is drop an egg in vinegar and come back in a few days to find…a bouncy egg!

Making a rubber egg is definitely a wait and see project but if you have a few days, you and your kids will be amazed at what happens to an eggshell after sitting in an acid like vinegar.

the layers of an egg

Making a rubber egg is also a great way for kids to learn about the layers of an egg. An egg has the following layers:

• The eggshell made from calcium carbonate
• Two shell membranes which protect bacteria from entering the egg
• The egg white or albumen which provides protein
• The yolk membrane which holds the egg yolk together
• The yolk which contains vitamins, minerals and fat

Once you dissolve the eggshell, the membranes will be on full display. Once you puncture the membrane you will see the white and yolk.

How To Make A Rubber Egg

Rubber Egg Materials

• Eggs
• Clear cup or jar
• Distilled White Vinegar
• Food Coloring
• Bowl of water

The Rubber Egg Experiment

The science of a rubber egg

Eggshells are made from calcium carbonate. Vinegar is an acid that reacts with calcium carbonate when the two come into contact with each other. The bubbles that form around the eggs over the course of a few days are actually carbon dioxide bubbles caused by the reaction between vinegar and calcium carbonate. Eventually the eggshell fully dissolves leaving only the outer membrane which is soft and flexible.

Once you remove the egg from the vinegar the calcium carbonate shell will be a chalky residue on the egg membrane.

Notice how the egg white is colored after sitting in colored vinegar, meaning the color penetrates the eggshell and also the membrane.

Turn it into a science fair project

Let’s turn this topic into an actual experiment! Here’s how you can take this to the science fair:

1. Ask yourself questions What other acidic liquids would dissolve an eggshell? Would soda, tomato juice, or citrus juice work? Why does the color seep through the membrane but the albumen doesn’t leak out of the membrane? Are some eggshells harder to dissolve than others?
2. Research Do research online and at the library to try and predict the answer to your question. Read about how the layers of an egg work and how liquids pass through the membrane. Research other liquids that calcium carbonate might react with. Research other substances that calcium carbonate is found in. Is it found in bones?
3. Make a hypothesis A hypothesis is your prediction of the answer to your question based on your research. It may or may not be true.
4. Experiment! Test your hypothesis by testing the variables and documenting them. Be sure to take notes of each experiment and what happens; this is called your data. 
5. Draw a conclusion Based on your experiments form a conclusion. Was your hypothesis correct? 
6. Share your findings Create a presentation with your findings. Include your research, hypothesis, the data you collected, and your conclusions. Be sure to include images and samples!

experiment examples

Try different types of eggs Do the experiment using eggs from different types of chickens. Do any take longer to dissolve?

Try different liquids What happens if you place eggs in other acidic liquids? Does tomato juice, citrus juice, diet coke, fruit juice, or cabbage juice work?

Use vinegar to dissolve other items made up of calcium Try chicken bones or limestone rocks. Do they also break down in vinegar?

More science projects to try

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