Egg in Vinegar Experiment
The egg in vinegar experiment, though pretty simple, gives your child the foundation knowledge on reactions between acids and bases. It goes on to change the chemical composition of an egg, making it rubbery on being dipped in vinegar for a few days. There are minor changes in the size of the egg too which can be measured over the period and plotted in a graph.
Rubber Egg Science Project
On soaking an egg in vinegar, the liquid dissolves its hard shell while exposing the thin membrane that is the only thing that holds the egg yolk and white.
- Raw egg
- White vinegar
- A clear jar or tall glass
- A big spoon
- Place the egg in the jar or glass such that it does not touch the walls of the container.
- Pour vinegar so as to cover the egg completely.
- Watch the egg closely. You should see bubbles forming on its surface. Note down your observations.
- Let the egg soak in the vinegar for one day.
- Use the spoon to scoop out the egg from the vinegar. You need to be very careful while doing this as the shell should already be partially dissolved by this time, leaving the egg tender.
- Now pour out the old vinegar, put the egg back in the container and cover it with fresh vinegar.
- Let the arrangement sit for another week.
- Scoop out the egg and rinse it carefully.
- Now you are left with an egg without a shell. Though it still looks like an egg, it has a translucent covering membrane that flexes when you squeeze it. If you shake it, you can see the egg yolk sloshing about in the egg white. You can even bounce it gently over hard surfaces.
Things You Can Try
- Perform the experiment on a hardboiled egg
- Try other variations of vinegar such as concentrated or apple cider vinegar. You can also replace vinegar with vinegar and baking soda solution, coke, corn syrup, salt water, tap water, etc. and look for any difference in the results.
Egg and Vinegar Experiment Video
Explanation for the Bouncy Egg
Eggshells are made of calcium carbonate (chemical formula CaCO3) while vinegar is acetic acid (chemical formula CH3COOH). The two chemically react to separate the calcium and carbonate parts. The calcium ions freely float in the vinegar while the carbonate ions form carbon dioxide that you can see in the form of bubbles.
Since the egg membrane is semi-permeable, it allows some of the vinegar to enter the interiors by osmosis, a process by which molecules of a solvent pass through a semi-permeable membrane to land themselves in a more concentrated solution from a less concentrated one. This makes the egg bigger and more delicate when you handle it. If the membrane ruptures, the insides of the egg will spill into the vinegar. After the experiment, if you leave the nude egg exposed to air, the atmospheric carbon dioxide reacts with the leftover calcium in the egg to make it regain rigidity after some time.
In the lab, it can also be used as a tool to grow dental health awareness in children. Teachers can explain that a similar reaction occurs when the bacteria sticking to their teeth create acids on reacting with sweets or coke (soda) when they have it. Their enamels get destroyed in the process. The fun yet educative activity has all the ingredients to become a favorite science fair project.