STEM (science, technology, engineering and math) sounds like it needs a lab. At home, it mostly needs a question, some paper cups and a willingness to let things fail. The ten activities in this guide use household materials and follow the same simple cycle engineers use: figure out the problem, make a plan, build it, test it, and make it better.
They range from unplugged coding a 4-year-old can play to a red-cabbage chemistry lab for 8- to 12-year-olds. Each card lists the age range, time and safety notes.
The one idea that makes any activity STEM
Science Buddies and TeachEngineering both describe the engineering design process in similar steps: define the problem, research, plan, build a prototype, test it, and redesign. You don’t need the vocabulary with young kids. You just need two questions:
- “What do you think will happen?” (a prediction)
- “What could we change to make it better?” (iteration)
Asking those questions turns tower building into engineering and a paper airplane into a physics experiment.
Teach the fair test early
When kids want to know whether a longer straw rocket flies farther, the answer only means something if everything else stays the same: the same person blowing, the same angle, the same launch line. This is the idea of a fair test, changing one thing at a time. The straw rockets, paper helicopters and foil boats are especially good for practicing it.
Recording results helps too. A 5-year-old can draw tally marks, an 8-year-old can fill in a table, and a 12-year-old can graph averages. Several printables on KidInfo, such as the paper bridge test log, work for any of these activities.
Activities by area
Technology and computational thinking
Robot commands is unplugged coding: one player is the robot and follows only the arrow cards the programmer lays out. When the robot walks into the couch, there’s a bug to find and fix. Kids practice sequencing and debugging with no screens at all.
Engineering
- Paper cup tower challenge: the tallest free-standing tower that can hold a book.
- Toothpick and marshmallow structures: discover why triangles are stronger than squares.
- Craft stick catapult: a lever to aim at a target, then move the fulcrum and see what changes.
For a full bridge-building challenge with a printable log, see build a paper bridge.
Physics: forces, air and water
- Straw rockets: design fins and nose cones and measure flight distance.
- Paper helicopters: explore air resistance by changing blade length and weight.
- Foil boat penny challenge: design a hull that carries the most cargo before sinking.
- Floating egg density test: an egg sinks in fresh water but floats once there’s enough salt.
- Water drop magnifier: a single drop becomes a lens.
Chemistry
The red cabbage color-change lab uses purple cabbage water as an indicator. Lemon juice and vinegar turn it pink; baking soda water turns it blue-green. An adult handles the stove and hot liquid, and the testing uses food-safe kitchen ingredients only. Never test household cleaning products.
Matching activities to age
- Ages 4–5 (with an adult doing setup): robot commands, cup towers, paper helicopters, straw rockets, sink-or-float with a foil boat (adult counts the coins).
- Ages 6–8: all of the above, plus the water drop magnifier, the floating egg and toothpick structures.
- Ages 9–12: the catapult with measurements, the cabbage chemistry lab, and redesign challenges with budgets and graphs.
Safety for home science
- Small items: coins, toothpicks, mini marshmallows and rubber bands are hazards for young children. Count coins back after the foil boat challenge.
- Heat and sharp tools: adults handle stoves, hot liquids, knives and cutting bottles or tubes.
- Projectiles: launch only soft pom-poms or paper, never toward faces or pets.
- Don’t eat the experiment: raw eggs, test liquids and craft materials stay out of mouths.
Pick by what your child loves
STEM clicks fastest when it connects to an existing interest:
- Loves building blocks or Lego: cup towers, toothpick structures, then the paper bridge.
- Loves throwing and launching: straw rockets, the catapult, paper helicopters.
- Loves water play: foil boats and the floating egg.
- Loves cooking: the red cabbage lab and the egg density test both happen in the kitchen.
- Loves games and rules: robot commands, then make up new command cards together.
- Loves looking closely: the water drop magnifier, then take it outside to look at leaves and bark.
A simple STEM notebook
Any notebook will do. For each activity, kids write or draw four things: the question (“Which boat holds the most?”), their prediction, what happened (with numbers if possible) and what they would change next time. Over a few months the notebook becomes a record of how their thinking has grown, and it’s a ready-made source of ideas for a school science fair.
How to talk about results
The conversation after a test is where most of the learning happens. Try these prompts instead of explaining the answer:
- “What surprised you?”
- “Why do you think the wide boat held more pennies?”
- “If we did it again, what one thing would you change?”
- “How could we make the test fairer?”
It’s fine to say “I don’t know, let’s find out.” Looking something up together in a library book or on NASA’s learning resources models how real scientists work.
A two-hour STEM afternoon
For a rainy afternoon or a no-school day, try this sequence for kids around 6–10:
- Robot commands (15 min): warm up with unplugged coding.
- Cup tower challenge (30 min): two rounds, measuring height each time.
- Snack break with the floating egg test (20 min).
- Straw rockets (30 min): design, launch, measure, redesign.
- Show and tell (15 min): each child explains their best design and what they changed.
Leave the materials out afterward. Kids often keep experimenting on their own once they have the idea.
When kids get frustrated
Things will collapse, sink and fly the wrong way. That’s part of STEM, but it can feel bad, especially for kids who like getting things right the first time. Help by:
- Naming it: “Engineers call that a failed test. It tells us something.”
- Shrinking the goal: make the tower stand for five seconds, not hold the book.
- Celebrating the redesign, not just the final result. The second boat that holds three more pennies is the real win.
- Taking a break and coming back after a snack.
Going further
NASA’s learning resources and Science Buddies’ activity library have many more experiments sorted by age and topic. If you’re considering a kit as a gift, our guide to STEM toys for kids explains age labels and safety checks. For a rainy afternoon that mixes STEM with active play, see rainy day activities for kids.