After scientists make observations, they begin to study! Scientists will read as much as they can about the subject they are observing. They will talk to other scientists and read other people’s experiments. A scientist is trying to understand the problem that they are investigating. It is through this type of research that scientists come to formulate a hypothesis.

What is a hypothesis? It is NOT an educated guess. Rather a hypothesis is a statement about a relationship and a prediction. It is a possible explanation (not an answer as science is not a math class)! A hypothesis must be testable.

Let’s think of a good hypothesis. A good hypothesis establishes a relationship first and then makes a prediction. For example, pretend we are interested in how temperature affects the speed of salt dissolving. We can make an experiment to help us investigate this relationship, but first we need a hypothesis to guide us. If an increase in temperature speeds up the dissolving process, then the salt in the glass with hot water will “disappear” before the salt in the cold water. This statement is a good hypothesis because it contains the following parts.

1. The statement establishes the relationship….temperature to dissolving.
2. The statement contains a prediction….the salt in the hot water will disappear first.
3. Finally this statement is testable. We can set up a controlled experiment to measure the effect temperature has on dissolution.

A good way to remember how to write a hypothesis is to remember the following: an if-then statement.

If….(state the relationship)….then (state the prediction). Enjoy writing those hypotheses!