Cohesion or cohesive force, which is a physical property of a material, is the intermolecular force of attraction between like molecules. For example, there is a force of attraction between the molecules of water which causes them to stick together. This science fair project idea is to prove that cohesion exist between water molecules through a simple test.
To prove that cohesion exist between water molecules.
- a paper cup or a Styrofoam (not less than 6 oz)
- a pencil
- Using the pencil punch four holes in the cup such that the holes are close to each other as possible in a straight line at the base of the cup.
- Make the cup to stand on the side of a sink such that the holes are on the sink side.
- Now fill the cup with water.
- Pinch the four streams of water together with your thumb and forefinger