What is a Scientific Hypothesis?

A scientific hypothesis is a testable, clear statement about what will happen in a science experiment, based on observations and prior knowledge.
It is written before an experiment takes place to determine if the experiment supports or refutes the hypothesis.

Step 1: Ask a question that is specific and can be researched using who, what, when, where, why, or how.
Examples of questions: How does sleep deprivation affect driving performance? What flavor of ice cream melts the fastest?
Step 2: Conduct preliminary research using reliable sources, case studies, and own observations or prior knowledge.
Gather research that addresses all sides of the question.
Step 3: Answer the initial question based on preliminary research.
Step 4: Write a hypothesis that includes the variables being studied and the predicted result of the experiment.

A good hypothesis is testable and clearly states the relationship between the variables being tested.
It should not be written as a question or an opinion.
It should include the variables being studied and the predicted outcome of the experiment.

"If a person experiences more sleep deprivation, then their driving performance will be negatively impacted."
"If a person gets 8 hours of sleep at night, then their memory during the day will improve."
"If teeth are brushed twice a day, then a person is less likely to develop cavities."

"It doesn't matter if you do your homework or not." (cannot be tested and lacks specific variables)
"Lightning is caused by ghosts in the sky." (cannot be tested)
"Fertilizer is better for flowers than it is for vegetable plants." (uses the word "better" which is an opinion)
"Ice cream tastes the best at midnight" (an opinion and cannot be tested)