Simple Experiment Fair

Every great scientific discovery started the same way — with a question. Scientists follow a series of steps called the scientific method to answer questions fairly and accurately.

The five steps of the scientific method

1. Step 1 — Question: Start with something you want to find out. "Does a plant grow taller with more water?" "Which objects sink?"
2. Step 2 — Prediction (hypothesis): Write down what you think will happen — before you test. "I predict the plant with more water will grow taller."
3. Step 3 — Method: Plan how you will test your prediction. What will you change? What will you keep the same? What will you measure?
4. Step 4 — Results: Carry out the experiment and record exactly what you observe — write numbers, draw sketches, or use a table.
5. Step 5 — Conclusion: Look at your results. Was your prediction correct? What did you find out? What would you do differently next time?

Three experiment ideas to choose from

• Plant and light: Does a plant grow toward a light source? Ask a grown-up to cut one hole in the side of a cardboard box, cover a seedling with the box, and observe over 3–5 days.
• Sink or float test: Choose 10 objects, predict which will sink or float, then test each in a bowl of water and compare predictions to results.
• Soap and pepper: Pour water into a bowl, sprinkle pepper on top, then dip a soapy finger into the center. Predict what happens — then observe how the soap breaks the thin skin on top of the water (surface tension).