Science fair rules for elementary school: what every district bans

Elementary science fairs share a handful of rules almost everywhere: no flames, no live animals at the fair, no mold or bacteria grown at home, kitchen chemicals only, a review before any project that tests people, and nothing wet, hot or powered on the display table. There is no national rule book for elementary fairs. Each district writes its own, usually as a PDF, so I read several and wrote down what they agree on. Your school's sheet always wins over anything here.

I built the science fair pages on Peabody around these rules, and not as a paragraph of advice: every project is checked in code against a list of banned words and a kitchen safe-list of materials before it can be shown. Here is what the rule sets say, where each rule comes from, and the reason behind it.

Where these rules come from

I read four rule sets closely on 30 October 2026:

• The UNM STEM-H Center's K–5 rules (revised August 2022), for New Mexico's affiliated fairs. The most complete elementary set I found.
• Washington County School District's rules (Utah, 2011), which include the board size limits.
• The Lowville elementary fair's rules, three rules on one page.
• The Society for Science's international rules, which most regional and state fairs follow, written for high school.

The rules, one by one

1. No flames of any kind. UNM, Washington County and Lowville all ban open flames. That rules out candles, matches and anything that burns, at home and at the fair. It's the most common rule there is.

2. No live animals at the fair. Lowville bans them outright, and UNM keeps organisms off the display. Projects that test animals need forms and a review committee at every level up to the international fair, which is why elementary projects stick to plants.

3. No mold or bacteria grown at home. UNM's K–5 rules say no microbe cultures at home. The mouldy-bread project is a classic, and it's exactly what this rule rules out. Older students do these only under a teacher, with forms.

4. Kitchen chemicals only. Lowville bans dangerous chemicals. Washington County allows safe household ones and limits a safe chemical on display to under a tablespoon. Baking soda, vinegar, salt and sugar are fine; anything from under the sink is not.

5. A review before testing people. Taste tests, surveys, reaction times and memory tests all use people as the thing being tested. UNM and the international rules both require review and consent first. Ask your teacher before starting one; some schools allow a family-only version with no names.

6. Nothing hot on display. UNM's limit is 75 °C. Hot water is fine in the kitchen with a grown-up pouring it, but not on the table at the fair.

7. No liquids, batteries or open containers on the table. UNM bans liquids and batteries on display, and Washington County bans open containers. Bring photos and drawings of the test instead.

8. The board has a size limit. Washington County's is 30 inches deep, 48 inches wide and 96 inches high. A standard 36 × 48 inch tri-fold fits, and Peabody's board layout tool works to that size.

9. The words are the child's. Washington County tells its judges to favour children's own language and drawings. Wobbly writing in a child's own words beats a grown-up's neat typing.

10. One student per project. Washington County allows one student per project. Some schools allow pairs; check yours.

What Peabody's projects leave out

Every project on Peabody keeps all ten. The check that runs over every project refuses words about flames, chemicals off the kitchen list, animals, cultures and people as the thing tested, and refuses any material that isn't on a kitchen safe-list. Hot water only appears on a step a grown-up does, and never below 2nd grade. The rules page for grown-ups lists them all with their sources.

Try tonight

If your child has a project idea already, hold it up against the ten rules above. If it trips one, find the version that doesn't: test the food instead of the people (which dip keeps an apple slice from going brown?), or plants instead of animals (do plants bend toward the window?). Or let Pick my project choose one that already fits.

Questions grown-ups ask

Is baking soda and vinegar allowed?

At every elementary fair I read, yes: they're kitchen things. Wear goggles in case of a splash, and bring a photo rather than the foam itself.

Can my child bring the experiment to the fair?

Usually not if it's wet, hot, powered or alive. Photos, drawings and the logbook are the usual answer, and judges expect them.

What if our school's rules are different?

Your school's sheet wins, every time. These are the rules the sheets I read have in common, not a replacement for yours.

Peabody (peabody.kids) is free through the end of 2026, with no ads and no sign-up. The library has stories to read once the board is done.