Brilliantly bouncy egg!

Activity overview

Run the activity

1. You’re going to watch a short video. The aim isn't to find right answers, it's to explore ideas and find out what they know.

• Do they know what might happen based on the image?

2. After you've watched the video, lead a discussion with your class:

• What do they think will happen to the egg when it has been soaked in the vinegar?
• How do they think the shell will behave - did they know it was possible to dissolve an eggshell? 
• Why do they think the egg bounces?
• Can they think of any other liquids that might be able to dissolve an eggshell?

3. Ask the class to describe what they saw using only one word.

Background science

To make this bouncy egg, a whole raw egg (shell and all) was left to soak in some vinegar for three days. Vinegar is a weak acid that slowly dissolves the eggshell, which is made from calcium carbonate. The inside of the egg is protected by a membrane, which keeps the egg white and yolk together. After 3 days in the vinegar, dropping the egg from a height of 15 to 20cm should see it bounce. Too much force, as seen in the video, and the membrane will burst! If you're going to try this experiment in the classroom, you will need to hard boil the egg beforehand.

Take it further

Activities  

Ask the children if they can think of any examples where they use a different liquid, other than water, to dissolve something? They could discuss acetone to dissolve nail varnish or white spirit with paint. 

There's a fact sheet, on the BBC Terrific Scientific site giving more details about how to repeat the bouncy egg activity. Alternatively, children could compare dissolving sweets in water or vinegar with this activity. 

Linked Explorify activities – our recommendations: 

For more activities on dissolving, try Have you ever tasted sugar in your cereal milk? and OOO Delicious drinks. For more eggy Explorify activities, why not try Standing on eggshells, or this Build an egg parachute Problem Solver.

Watch 

Watch this BBC film introducing dissolving. The APBI have a series of animations on changing states and materials. This video rehearses the vocabulary and the key concepts.