Experimental Hypothesis

If  the earthworms are exposed to sunlight, then they will crawl towards the shaded soil because the earthworms prefer shade to bright light.

Null Hypothesis 

If the earthworms are exposed to sunlight, then they will not crawl to the shade because earthworms prefer bright light to shade.  

How Do Earthworms React To Light?

Purpose

The purpose of this experiment is to investigate how earthworms react to differing amounts of light.
(The purpose is important because it lets others know exactly what you are investigating right in the beginning.)