How to Write a Hypothesis: Lesson for Kids

Instructor: Jennifer Farrell

Jen has taught Science in accredited schools in North & South America for thirteen years and has a degree in Sociology (Epidemiology & Aids Research).

In this lesson, we investigate why scientist use a hypothesis, practice how to write a hypothesis, and learn some helpful hints for writing a hypothesis that would make Einstein proud.

What Is a Hypothesis?

Imagine you're hiking in the forest and come across one burnt tree. You might ask yourself, 'what happened to this tree?' You might then try to answer your own question. Maybe there was a fire. No, that isn't possible because the other trees are healthy. Maybe it was lightning? That seems more likely - there have been thunderstorms every day this week, this tree is the tallest in the forest, and lightning can burn objects. Congratulations, you just created what scientists refer to as a hypothesis!

A hypothesis helps you answer a question.
thinking about a hypothesis

A hypothesis (pronounced hi-PAW-thuh-sis; plural hypotheses) is a prediction or possible explanation for a question that needs to be investigated. Coming up with a hypothesis is one step in the scientific method, which we use when we perform science experiments. You may have heard your parents or teacher use the phrase 'make an educated guess.' A hypothesis is kind of like that. It uses what you already know in order to make a well-thought out prediction.

If you don't know much about a topic, then you'll need to do some research before making a hypothesis or moving forward in your experiment.

How to Write a Hypothesis

Writing a hypothesis is a step in the scientific method.
clip art

Let's begin by looking at two different sentences:

  1. The sun will rise tomorrow.
  2. If I use fertilizer, then the plants will produce more flowers.

The first sentence is a statement and cannot be tested. However, the second sentence is a question that can be proved or disproved by doing a test. All hypotheses must be written so they can be tested with an experiment. Not only are experiments super fun, but they give you an answer to the question you're trying to answer with your hypothesis.

Writing a hypothesis is like following a recipe. You will use the same basic ingredients as your foundation each time. Follow this easy formula to write a strong hypothesis:

If (I do this), then (this will happen). We call this an if -> then statement.

  1. If I use fertilizer, then the plants will produce more flowers.
  2. If I eat ice cream everyday, then I will gain weight.

Writing your hypothesis as an if -> then statement is helpful because it includes variables. Variables are the parts of your hypothesis that are being measured, and that change so you can get your measurements. Having variables in your hypothesis will assure it is testable. In other words, a test can be done to prove or disprove it.

What are our variables in the above hypotheses?

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