20 best sites for STEM projects at home

Over a thousand guided projects and experiments sorted by grade and interest, including AI and coding projects. The best place to find a science fair idea.

Watch for: Some ads and kit links.

Museum-tested experiments made with cheap materials like cups, magnets and string. Each one has a clear explanation of the science, so kids learn the idea and not just the trick.

Open-ended build projects like chain reactions, marble machines and scribbling robots, from the Exploratorium. Great for kids who like to mess around and figure things out.

Hands-on space and engineering activities from NASA, from paper rockets and straw rockets to Mars rover design challenges. Sorted by grade, with clear materials lists.

Space crafts, games and experiments for younger kids, written by NASA scientists. Good for making a model of the solar system or a homemade sundial.

Virtual labs for physics, chemistry and math when a real experiment is too hard, too dangerous or too messy. Kids change one thing and see what happens.

Engineering challenge videos from PBS KIDS that walk kids through designing, testing and fixing a build. Each one uses cheap, everyday materials. Many challenges take under an hour.

Over a thousand free engineering lessons and hands-on activities written for teachers but easy to use at home. Search by grade and topic. Activities list time, cost and materials.

Simple science and STEM activities for preschool and early grades, like slime, volcanoes, ice melts and LEGO challenges. Quick to set up on a busy afternoon.

Art-meets-engineering projects from a designer, like spinning tops, paper circuits and marble mazes. The results look good enough to keep. Most projects use paper, tape and household items, so you can start today.

A library of free experiment instructions, from Mentos geysers to density towers, from a science teacher turned TV presenter. Kits are sold too. Most experiments use kitchen supplies.

Real citizen science online: classify galaxies, count penguins or transcribe old ship logs for working researchers. Kids see their work help real science. Projects take minutes and need no science background.

Watch for: Kids under 16 should join with a parent. Discussion boards are public.

A searchable directory of citizen science projects you can join from home, your backyard or a local park. Filter by age and topic. Many projects need only a phone and a walk.

Snap a photo of a plant or bug and AI suggests what it is, then human experts confirm. Teens help real biodiversity research and learn how AI and people work together.

Watch for: Accounts are 13+. Younger kids can use the Seek app, which does not need an account. Photos may share location.

A pocket-sized programmable board with lights, buttons and sensors. Free projects range from step counters to simple AI gesture models built with kids' own data.

Interactive lessons from the University of Utah on DNA, cells, heredity and the brain, with virtual labs. Clear and well designed for middle and high school.

Train an AI to recognize your hand signals, sounds or poses in the browser. It works as a home science experiment about how AI learns from examples.

Watch for: Uses the webcam or microphone.

Free virtual field trips and lessons from The Nature Conservancy about nature and the science of conservation, with videos and activity guides. Each trip comes with a short guide for families.

Monthly project boxes with everything needed to build gadgets and experiments, sorted by age from babies to teens. No shopping for parts. Lines for older kids cover electronics and engineering.

Watch for: Easy to forget the auto-renew.

Mark Rober's build-box subscription: a toy to build each month with a video that explains the physics behind it. Fun for fans of his channel.