Science Fair Projects for High Schoolers: 31 Ideas Sorted by ISEF Category

Last updated: October 31, 2026

A good science fair project for high schoolers asks a question nobody has answered in exactly that way, measures a result with real numbers, and repeats each test enough times to trust the outcome. Judges at the high school level expect more than a demonstration. They want a clear question, a controlled method, statistics and an honest discussion of what went wrong. Below are 31 project ideas, sorted by the 22 Regeneron ISEF categories, with what to measure and which ones need approval before you start. Rules and dates were checked on the Society for Science website in October 2026.

The projects judges remember start with a question the student truly cares about. Find yours, and build it with a PhD mentor. See if you qualify for the STEM Research Program →

What makes a high school project different

Middle school projects usually test one variable with a simple setup. High school projects are judged more like real research. The strongest projects have:

An original question. Not "does salt water conduct electricity," but "how does salt concentration change the power output of a saltwater battery, and where does the gain stop?"
A measured result. A number from an instrument, a sensor, a titration or a dataset, not an opinion.
Controls and replication. A control group, fixed conditions, and several trials or samples per condition.
Statistics. At least averages, variation and a graph. Better: a statistical test or a model fitted to the data.
Your own work. You can have help and a mentor, but you must be able to explain every step and every decision.
A logbook. A dated record of every trial, change and mistake.

The rules also say what doesn't count. Society for Science says demonstrations, literature reviews, "library" research and "explanation" models are not appropriate for ISEF.

Check the rules before you choose

Most fairs that lead to ISEF follow the International Rules for Pre-College Science Research, published by Society for Science every year. Check these before you pick an idea:

Human participants need IRB approval first. Surveys, memory tests, taste tests and reaction-time tests all count. An Institutional Review Board must approve your plan before you collect any data, and participants must give informed consent.
Vertebrate animals need approval first. A Scientific Review Committee (SRC) must approve the project before you start, and many projects also need a qualified scientist.
Bacteria, mold and other microorganisms need approval first. The rules prohibit culturing potentially hazardous biological agents in a home environment, even low-risk ones.
Hazardous chemicals, activities and devices have their own rules. These include lasers, drones, radiation, firearms and prescription drugs. Document a risk assessment and follow the supervision rules for your project.
Plan your timeline. For ISEF 2027, your project may include no more than 12 continuous months of research, and none of it may be from before January 2026.
AI rules. You may use AI as a cited resource, but you may not use generative AI to write your research plan, abstract or poster.

The ideas below mark which ones need IRB or SRC approval. Ideas without a mark usually need only the standard forms, but your fair's SRC has the final word.

A sharp question, a sound method, the right approvals: a PhD mentor helps you get each one right from the first week. See if you qualify for the STEM Research Program →

Physics and astronomy project ideas

Measure air drag with a smartphone. Drop objects of different shapes and record the fall with the phone's accelerometer (free apps such as phyphox read the sensors). Compare measured drag with the theoretical value.
Magnetic braking and temperature. Drop a strong magnet through copper and aluminum tubes at different temperatures. Measure fall time and relate it to how the metal's electrical conductivity changes.
Solar panel efficiency vs heat. Measure a small panel's power output at a fixed light level while its temperature changes. Find how much efficiency is lost per degree.
Find an exoplanet transit in public data. Use NASA's public TESS data to measure the dip in a star's brightness as a planet passes, and estimate the planet's size.
Sound absorption of everyday materials. Build a test box, play a fixed tone and measure the sound level through different materials. Compare cost against absorption.

Engineering project ideas

Wind turbine blade shape. 3D print or cut three blade designs and measure power output at several wind speeds from a fan.
Cool roof coatings. Paint identical small roofs with different coatings and log the temperature under each in direct sun over several days.
Strength-to-weight of truss designs. Build bridges from the same material and mass, and load them until failure.
Low-cost soil moisture irrigation. Build a microcontroller (such as Arduino) system that waters plants only when the soil is dry. Measure water saved against a timer-based system with the same plant growth.
A low-cost seismometer or vibration sensor. Build one, calibrate it against a known source, and test how well it detects small vibrations.

Chemistry and biochemistry project ideas

Vitamin C loss in juice. Use iodine titration to measure how vitamin C drops with storage temperature and time.
Bioplastic strength. Make starch-based plastic with different amounts of glycerol. Measure tensile strength and how fast each sample breaks down in soil.
Saltwater battery performance. Change electrolyte concentration or electrode metal and measure voltage, current and how long the battery lasts under a fixed load.
Enzyme activity vs pH. Measure the oxygen produced by the catalase enzyme in potato extract at different pH levels and temperatures.
Natural pH indicators and light. Extract color from red cabbage and test how quickly the indicator fades under different light conditions.

Earth and environmental science project ideas

Microplastics in local water. Filter samples from several local sites and count particles under a microscope. Compare sites near and far from roads or drains.
Map your neighborhood's heat island. Place temperature loggers over grass, asphalt, shade and roofs, and compare daily highs and lows.
Test a low-cost air quality sensor. Place a low-cost PM2.5 sensor near an official monitor (EPA's AirNow publishes the data) and measure how accurate it is under different humidity levels.
Erosion and ground cover. Use trays of soil with different covers (bare, mulch, grass) and measure soil lost after a fixed amount of simulated rain.

Plant science project ideas

Duckweed and pollutants. Grow duckweed in water with different levels of salt, detergent or microplastic, and count plant growth over several weeks.
Salt tolerance of crop varieties. Compare how different varieties of the same crop germinate and grow at different salt levels.
Do invasive plants suppress native seeds? Make extracts from an invasive plant's leaves and test their effect on native seed germination.

Animal science project ideas (invertebrates)

Daphnia heart rate. Measure how temperature or caffeine concentration changes the heart rate of Daphnia (water fleas) under a microscope.
Planarian regeneration. Test how temperature or light changes how fast planarian flatworms regenerate.

The vertebrate animal rules cover all vertebrates, including fish, and cephalopods such as octopus. Daphnia and planaria are neither, but check your fair's rules, treat the animals humanely and never release them into the environment, which the rules prohibit.

Computational biology, math and software project ideas

Plant disease classifier. Train an image classifier on a public plant disease dataset, then test how accuracy drops on your own photos taken in real light.
Model a flu season. Fit an epidemic model (such as an SIR model) to public CDC flu data and test how well it predicts the peak.
Predict air quality from weather. Use public weather and air quality data to build a model that predicts poor air days, and test it on a year you didn't train on.
Explore protein mutations. Use the AlphaFold Protein Structure Database to compare predicted structures for a protein and its known disease-linked variants.
A computer search in combinatorics or graph theory. Write a program to find examples or counterexamples for an open or lesser-known pattern, then try to prove what the data suggest.

Behavioral science project ideas (IRB approval required)

Background music and memory. Test whether music with or without lyrics changes short-term recall.
Phone notifications and reading. Measure reading comprehension with and without notification sounds.

Both need IRB approval and informed consent before you start. For more ideas in this area, see psychology research topics for high school students.

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The 22 ISEF categories

If you plan to compete at ISEF, choose the category that best fits your project. The categories for 2027 are:

Animal Sciences
Behavioral and Social Sciences
Biochemistry
Biomedical and Health Sciences
Biomedical Engineering
Cellular and Molecular Biology
Chemistry
Computational Biology and Bioinformatics
Earth and Environmental Sciences
Embedded Systems
Energy: Sustainable Materials and Design
Engineering Technology: Statics and Dynamics
Environmental Engineering
Materials Science
Mathematics
Microbiology
Physics and Astronomy
Plant Sciences
Robotics and Intelligent Machines
Systems Software
Technology Enhances the Arts
Translational Medical Science

A 12-week plan from idea to fair

Weeks 1–2: choose the question. Read about the topic, pick two or three ideas and check each against the rules. Choose one you can test many times.
Week 3: write the research plan. State the question, the variables, the method, the risks and how you will analyze the data. Get IRB or SRC approval now if you need it.
Weeks 4–8: collect data. Record everything in the logbook, including failed trials.
Weeks 9–10: analyze. Make graphs, calculate variation and run a statistical test if your data allow it.
Week 11: write and build. Write the abstract and build the board: question, method, results, conclusion and next steps.
Week 12: practice. Judges will ask why you chose your method and what you would change. Practice your answers out loud.

For help with the write-up, see how to write a research paper in high school. For more topic ideas, see research topics for high school students.

Where a high school project can go

Regeneron ISEF. The top level of the affiliated fair system, for grades 9 to 12. You qualify by winning at a Society-affiliated fair. See how to qualify for ISEF.
Regeneron Science Talent Search (STS). A research competition for high school seniors. About 2,600 students enter each year, and $3.1 million in awards are given, including a $250,000 top prize. The 2027 application closes November 5, 2026, at 8 p.m. ET. The top 300 scholars will be announced January 7, 2027, and the top 40 finalists January 21, 2027.
Junior Science and Humanities Symposium (JSHS). Students do original research and present it at regional symposia, competing for scholarships. JSHS is backed by the Department of War and administered by the National Science Teaching Association.
Science Olympiad. A team competition rather than a research fair. See our Science Olympiad guide.

Younger students can compete through the Thermo Fisher Scientific Junior Innovators Challenge for grades 6 to 8. See science fair project ideas for middle school.

Imagine standing at your board, ready for every judge's question, because the work is truly yours. See if you qualify for the STEM Research Program →

Frequently asked questions

What is the best science fair project for high school? The one with a question you care about and can measure many times. A simple setup with careful data and good statistics beats an impressive idea you can only test once.

What are easy science fair projects for high school? Projects with cheap materials and quick trials: magnetic braking in tubes, vitamin C titration, solar panel output vs temperature, duckweed growth, or a data project using public datasets. "Easy" should mean easy to run many times, not easy to think about.

Can I do a science fair project with bacteria at home? No, not for fairs that follow the International Rules. Culturing potentially hazardous biological agents, even low-risk ones, is prohibited in a home environment. Projects with microorganisms need SRC approval and a proper lab.

Can I use a survey in my science fair project? Yes, but surveys count as research with human participants. You need IRB approval before you collect any data, and participants must give informed consent.

How long should a high school science fair project take? Plan for at least 10 to 12 weeks from idea to fair. For ISEF 2027, research must fit within 12 continuous months and start no earlier than January 2026.

Can I get help from a mentor? Yes, as long as the work you present is your own and you disclose the help you received. For ISEF, the research plan must separate your work from your mentor's. See how to find a research mentor in high school.

Sources

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