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Investigation: Compose Hypothesis

After gathering background research, students will be better prepared to formulate a hypothesis. More than a random guess, a hypothesis is a testable statement based on background knowledge, research, or scientific reason. A hypothesis states the anticipated cause and effect that may be observed during the investigation. Consider the following hypothesis:

If ice is placed in a Styrofoam container, it will take longer to melt than if placed in a plastic or glass container. I think this is true because my research shows that a lot of people purchase Styrofoam coolers to keep drinks cool.

The time it takes for ice to melt (dependent variable) depends on the type of container used (independent variable.). A hypothesis shows the relationship among variables in the investigation and often (but not always) uses the words if and then.

Take a look at these additional examples:

  • If a mixture of vinegar and baking soda are used, then more stains may be removed. I think this because vinegar and baking soda are used in many different cleaning products.
  • Tomato plants will grow best if they get at least 12 hours of light each day. This is based on research that says that tomatoes need lots of light.
  • When an object has a volume greater than 30 cubic centimeters, then it will sink in water. In the past, I have seen big objects sink.

“The important thing about a hypothesis is not its initial accuracy. For instance, looking at the last example, students are likely to determine that the materials used or the shape of those materials will also impact an object’s ability to sink or float. For students who worry that their hypothesis does not match their experimental results, parents and teachers should emphasize the idea that all hypotheses are valuable regardless of their truth if they lead to fruitful investigations.” (Benchmarks for Science Literacy, 2003)