A tall glass
Cooking oil (like coconut oil or olive oil)
Fill half the glass with water.
Fill the other half of the glass with cooking oil.
Place the pencil in the glass
Look at the pencil from the side of the glass and observe how it appears to be.
How does this happen?
Light generally bends when it passes from one substance to another. The bending of light is called refraction. Light waves can travel through air, water, oil and glass, but not through a pencil.
Air, being least dense, makes the pencil seem narrow. Oil, being denser than air, makes the pencil seem wide and water, being the densest among the three, makes the pencil seem broader. The pencil also appears bent and broken at different angles because of the light waves.