Get Some Great Inspiration With These Science Fair Topic Ideas

Categories to Inspire Projects

Elementary school students’ science fair topic ideas usually fall into one of seven main categories. A brief description of each of those categories might help your child decide what type of project to choose for the science fair.



Girl explaining her science project to brother
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Biology is the study of living things and how they grow. This includes plants, animals, bacteria, and fungi. Projects focused on bacteria or plants are best as there can be ethical concerns and restrictions on using animals for science fair projects.

Project ideas can include experiments which look at how a factor such as light, temperature, water, soil acidity, or fertilizer affects plant growth.

If your child has access to Petri dishes and agar, an experiment can show bacterial and fungal growth from various sources such as hands, toothbrushes, swabs of household fixtures, or by leaving the plates uncovered in different rooms.



Chemistry is the study of substances and what happens when you combine them to create compounds. Parents may want to supervise younger children, and you will need gloves and safety goggles if an experiment calls for any chemicals to be involved.

Growing crystals and exploring the effects of temperature and moisture on the growth rate is one project idea. Testing the pH of various drinks, fruit juices, water, and vinegar can explore acidity and alkalinity.

The traditional vinegar-and-baking-soda volcano is another fun chemistry experiment that can overlap with earth science.


Earth Science

Earth science encompasses things such weather, climate, volcanoes, fossils, rocks, and the ocean. A project focus might include an analysis of where certain types of weather occur and what the common factors produce that weather phenomenon. A child could also explore different types of rocks and minerals and where they may be found.



Electronics projects look at how electricity is conducted and can be controlled. Project ideas that include experiments with circuit boards and batteries, such as the classic potato battery. Older students may want to make a crystal radio.



Astronomy is the study of the universe and all its components including stars, planets, moons, meteors and other celestial bodies. One astronomical project idea would be to build a sundial and to discover and explain why it works. Studying star charts and current astronomical conditions and planet positions could provide project ideas as well.



Engineering involves designing, creating and studying the function of machines and their processes. An engineering project might involve designing a machine with an entirely new function using various simple machines in the process, such as a Rube Goldberg machine.



Physicists study matter and energy. This may sound complicated until you know that this includes light, sound, magnetism, and motion.

The egg-in-a-bottle experiment is a classic in which paper is burned in the bottom of a bottle and an egg at the mouth of the bottle is drawn into it due to the change in pressure.

Making rockets or finding the best shape for a paper airplane can be fun physics projects. A child can also explore materials that conduct heat the best or that are the best insulators.

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