Science Fair Project Ideas

Many science fair projects are demonstrations, like a “baking soda volcano.” Judges want experiments that answer a unique question, not just repeat a known result. A great project starts with a great question.

This guide helps you find one. We provide 200+ testable project ideas and show how to design an experiment.

What is a Science Fair Project?

A science fair project is a hands-on experiment you design to answer a testable question using the scientific method. It is not a demonstration (like a volcano) or a research report (like a paper about dinosaurs). You must form a hypothesis, test it, and present your data.

Key Types of Science Fair Projects

Your project will likely be one of these types:

• Experimental: The most common type. You change one variable to see its effect on another (e.g., “How does liquid type affect plant growth?”).
• Engineering: You design, build, and test a solution to a problem (e.g., “Building a better water filter”).
• Observational/Data: You observe a system or analyze existing data to find a pattern (e.g., “Tracking and mapping bird populations in a local park”).

For high school projects, see our AP Research topics for more advanced ideas.

How to Choose a Project in 4 Steps

Start with a topic you genuinely care about (e.g., plants, video games, music). Then, ask a specific question about it. “Why do plants grow?” is too broad. “How does music affect plant growth?” is a testable question.

Turn your question into a clear, testable statement. A hypothesis is an “if, then” statement. E.g., “If I play classical music for a bean plant, then it will grow taller than a plant with no music.”

How will you test your hypothesis? You must define your variables:

• Independent Variable: The one thing you *change* (e.g., the type of music).
• Dependent Variable: The thing you *measure* (e.g., plant height).
• Controlled Variables: All the things you keep *the same* (e.g., sunlight, water, pot size).

Can you realistically do this? Do you have the time, money, and materials? Check your school’s rules (e.g., no experiments on live animals, no hazardous chemicals). A simple, well-run experiment is better than a complex, failed one.

Science Fair Project Ideas by Field

Here are project ideas, organized by scientific field.

Biology & Environmental Science

For more advanced ideas, see our biology research topics guide.

Chemistry

Physics & Engineering

Psychology & Social Sciences

Note: Most schools have strict rules against psychological experiments on people. Check with your teacher first. These projects are often simple surveys.

These ideas can be expanded into full psychology research papers at the college level.