Sink or Float Egg Experiment

This simple science experiment investigates the laws of density and children can discover just how easy it is to make make an egg float!

For this activity:

You will need: 2 similar sized eggs, 2 identically sized tall containers or glasses, water, salt.
Begin with observing the 2 eggs. In order to make the experiment fair, they need to be the same size and weight and both must be raw eggs. Discuss – do you think that the eggs will sink or float when placed in water? Do you think it’s possible to make them float? If so, how can this happen? Write down your hypothesis (prediction).
Fill one glass about 3/4 full of water and carefully place the egg into the glass. What happens to the egg? In pure water, the egg will sink.
Fill the second glass with the same amount of water. Add 3 Tablespoons of salt and stir until completely dissolved. What do you think will happen if you place the egg into the glass with the salt water? Observe the egg floating. Discuss – why did this happen?
The egg will sink in regular tap water because the density of the egg is greater than the density of water. By adding enough salt, you increase the density of the water so that it is higher than the density of the egg and the egg will float.