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Task 3 - Composing your hypothesis

This task is due for the second lesson.

Both, task 2 and 3 must be fulfilled before next lesson.

Use your laboratory notebook to record the task.

CK-12 Foundation. The Scientific Method (CC-by-SA-3.0)

Compose hypothesis

After gathering background research, the next step is to formulate a hypothesis. More than a random guess, a hypothesis is a testable statement based on background knowledge, research, or scientific reason.

A scientific hypothesis is a proposed explanation for a phenomenon.

A hypothesis leads to one or more predictions that can be tested by experimenting (one or two predictions is enough to tackle for your science project).

Predictions often take the shape of "If ____then ____" statements, but do not have to. Predictions should include both an independent variable (the factor you change in an experiment) and a dependent variable (the factor you observe or measure in an experiment).


Science Buddies - Science Fair Projects - Hypothesis

Science Fair Central - Scientific Projects - Steps

Wikipedia - Hypothesis

Lincoln Lutheran - Science - Hypothesis Statement

Hypothesis examples




How does the size of a dog affect how much food it eats?

Larger animals of the same species expend more energy than smaller animals of the same type. To get the energy their bodies need, the larger animals eat more food.

If I let a 70-pound dog and a 30-pound dog eat as much food as they want, then the 70-pound dog will eat more than the 30-pound dog.

Does fertilizer make a plant grow bigger?

Plants need many types of nutrients to grow. Fertilizer adds those nutrients to the soil, thus allowing plants to grow more.

If I add fertilizer to the soil of some tomato seedlings, but not others, then the seedlings that got fertilizer will grow taller and have more leaves than the non-fertilized ones.

Adapted from: Science Buddies - Science Fair Projects - Writing a Hypothesis

Wrong hypothesis?

Don’t worry if your hypothesis does not match your experimental results, all hypotheses are valuable regardless of their truth if they lead to fruitful investigations.

The point of a science project is not to prove your hypothesis right. The point is to understand more about how the natural world works.

Adapted from: Science Buddies - Science Fair Projects - Writing a Hypothesis

Hypothesis checklist

What makes a Good Hypothesis?

  • Is the hypothesis based on information from reference materials about the topic?
  • Can at least one clear prediction be made from the hypothesis?
  • Are predictions resulting from the hypothesis testable in an experiment?
  • Does the prediction have both an independent variable (something you change) and a dependent variable (something you observe or measure)?

For a Good Hypothesis, You Should Answer "Yes" to Every Question.

Adapted from:Science Buddies - Science Fair Projects - Hypothesis