Science Challenge

Get involved in our July Science Challenge to make an egg float!

What you'll need:

  • A bowl or large glass
  • Tap water
  • Table salt
  • 1 egg


  1. Fill the bowl/glass about ⅔ full with tap water.
  2. Drop the egg carefully into the bowl/glass and observe it sinking to the bottom.
  3. Remove the egg and add 5 tablespoons of salt to the water. (If the egg sinks, add more salt until it floats).
  4. When there is enough salt in the water, watch the egg float to the top.

The Science

Objects sink when they are more dense than the water. The word density describes how much space an object takes up (its volume) in relation to the amount of matter in that object (its mass). By adding salt, the water becomes more dense and this causes the egg to float.

Scientist of the Month

Our scientist of the month for July is Archimedes.
Can you write some facts about this amazing Scientist?

Listen to Mr Archimedes’ Bath

The Science behind Archimedes’ principle

You can download our July Science Challenge PDF below.