Bouncy Egg

Humpty Dumpty is probably the most famous egg that ever existed...right? As the story goes, Humpty Dumpty sat on a wall, Humpty Dumpty had a great fall… but what if he didn’t crack?

In this experiment, we’ll be exploring how vinegar works its magic on an eggshell, transforming it into something completely different! Get ready to see what happens when we take away the eggshell and leave the egg with its soft, bouncy membrane. Let’s find out if Humpty Dumpty could survive a fall after all!

Before we get started, let's make some guesses about what might happen. Scientists like to make predictions, or hypotheses, before they do experiments. It helps them figure out what to expect and why things happen the way they do.

Have a go at making your best guess using the questions below:

1. Do you think the egg will get bigger or smaller after it's been sitting in the vinegar?
2. What do you think will happen to the egg shell?
3. What do you think will happen to the yolk of the egg?

Tīmata! Let’s get started! 

• Egg - hēki
• Jar (with a lid)
• Vinegar - winika

Let's begin!

1. Pour some vinegar into a jar. Make sure you have enough to cover your egg.
2. Place your egg into the jar and close the lid.
3. Now it’s time to be patient, wait 3-4 days before opening the jar
4. Gently drop the egg onto a surface (start low and work your way higher...be careful, it can get messy!)

Extra for Experts!

• Once your egg is bouncy, see how high you can drop it without it cracking! (Again, this might be extra messy!)
• Add a splash of colour by adding a few drops of food colouring to the vinegar before adding the egg.
• Grab a torch and shine a light through your shell-less egg, what do you notice? Compare this with a normal egg.

1. What did you notice happening to the egg while it was in the vinegar?
2. Do you think the same thing would happen if the egg was sitting in water?
3. How did the egg feel when you touched it after it had been in vinegar for a few days?
4. What role did the vinegar (acid) play in this experiment?
5. Why do you think the vinegar only affects the shell?

Dissolving the shell

The shell of an egg that is hard, and protective is mostly made of calcium carbonate, which is the same material found in chalk and seashells.

When vinegar (an acid) gets to work on the shell, it reacts with the calcium carbonate and starts fizzing away, releasing carbon dioxide bubbles (that’s why you see the egg getting all bubbly).

What’s left behind is the stretchy inner layer called the membrane. It’s tough enough to hold the raw egg inside and flexible enough to turn your egg bouncy!

The Egg Gets Bigger!

As the shell disappears, some of the water from the vinegar moves through the soft egg covering. This makes the egg fill up with water and grow bigger!