What is a hypothesis?
A hypothesis is a testable prediction or proposed explanation for something, based on what is already known. Scientists design experiments to see whether the evidence supports it.
A good hypothesis is specific and can be tested and possibly proven wrong. For example: If plants get more sunlight, then they will grow taller. A scientist can test this by growing identical plants with different amounts of light while keeping everything else the same, then measuring the results.
If experiments repeatedly support a hypothesis, scientists gain confidence in it, but they never consider it absolutely proven, because new evidence could change things. If results contradict a hypothesis, it is rejected or revised. This process of testing and refining is at the heart of science.
Hypothesis and theory
In everyday language, theory often means a guess, but in science, a theory is a well-tested explanation supported by large amounts of evidence, such as the theory of evolution or the theory of relativity. A hypothesis is a smaller, more specific idea that is tested along the way.
Did You Know?
The word hypothesis comes from Greek words meaning to put under, suggesting an idea placed beneath an argument as its foundation.