2 Clear Jars or Glasses
About 5tbsp. Salt (preferably Kosher salt, but table salt will work)
1. Fill one glass with about 2 cups of tap water.
2. Fill the other glass with about 2 cups of warm water and stir in salt until dissolved.
3. Gently place an egg in each glass.
4. Observe the difference!
The answer is all in density. An egg is denser than fresh water and sinks. But salt water is denser than fresh water – when salt is added and dissolves, it breaks down into ions that are then attracted to the water molecules. This attraction causes them to bind tightly and now there are more particles in the water compared to fresh. The egg is now pushing on a denser liquid and does not sink.
Think about this the next time you are at the beach – it is much easier to float in the open salt water of the ocean than a lake or swimming pool!