Purpose
To demonstrate how tiny water droplets in clouds grow into raindrops.
Materials
- eyedropper
- tap water
- clear plastic lid (coffee can lid)
- pencil
Procedure
- Fill the eyedropper with water.
- Hold the plastic lid in your hand, bottom side up.
- Squeeze as many separate drops of water as will fit on the lid.
- Quickly turn the lid over.
- Use the point of a pencil to move the tiny drops of water together.
Results
Some of the water falls when the lid is inverted, leaving small drops on the lid. The small drops combine, forming larger drops that eventually fall.
Why?
Water molecules have an attraction for each other. This attraction is due to the fact that each molecule has a positive and a negative side. The positive side of the molecule attracts the negative side of another molecule. The tiny water droplets on the plastic lid, as well as in clouds, join to form larger, heavier drops, which fall. The falling drops from clouds are called raindrops.