• A transparent jar
• Water
• Salt
• Egg

• Take the transparent jar, fill it with water.
• Now with much care, place an egg inside the water.
• What happens, the egg sinks in water due to the heavy density of egg.
• Now take the egg out of the jar.
• Now, make the child to add 10 table spoons of water into the jar.
• Wait for some time, so that the salt dissolves in water.
• Ask the child whether the salt can be seen now in water.
• This is the dissolving property.
• Now place the egg inside the water.
• What happens. Now the egg floats.
• How does this happen. This is because the density of water increases after the salt is being added.

• The density of water increases after the salt is being added.
  

This is why in dead sea, a man floats, beacause the density of the water is much greater in dead sea compared to other sea water..

The same experiment can be done without taking the egg outside the water. Keep on adding salt and let it dissolve. Let the child watch the egg coming up within a short time.