Free STEM games for kids, students, teachers and anyone who never stopped being curious. Nothing here is a video — every planet, bead and pendulum is being solved by real equations in your browser, right now. Drag it, break it, crank gravity to zero and see what happens.
Six numbers, one target, and a hundred ways to get there. Everybody in the world gets the same puzzle each day, and it changes at midnight. Build a streak — or have tomorrow's emailed to you.
Fling planets around a star and find out if you made an ellipse, a slingshot or a disaster. Crash worlds together to build bigger ones.
Play → Ages 7+ · gravity, orbits chaos ๐Two sticks joined together, swinging. Launch twelve near-identical copies and watch a millionth of a degree turn into total disagreement.
Play → Ages 9+ · chaos, energy probability ๐ฑRain thousands of beads through a forest of pegs. Nobody tells them to make a bell curve. They make one anyway. Then load the coin and watch it lean.
Play → Ages 8+ · probability, statistics waves ๐ผA Victorian drawing machine made of swinging pendulums. Tune it to a musical chord and the scribble snaps into a perfect knot. Save your art.
Play → Ages 6+ · waves, music & mathDrop sticks on a striped floor. Count the ones touching a line. Out comes ฯ — measured by pure randomness that has never seen a circle.
Play → Ages 10+ · pi, probability unsolved ๐งEven? Halve it. Odd? Triple it and add one. Every number ever tried crashes down to 1 — and nobody on Earth can prove it always will.
Play → Ages 8+ · sequences, open problems forensics ๐In real data, numbers start with "1" about 30% of the time and "9" almost never. Auditors use this to catch fraud. Try to fake a list that fools it.
Play → Ages 11+ · data, logarithmsThink of any 4-digit number. Shuffle the digits biggest-first, subtract smallest-first, repeat. Within seven steps you land on 6174. Always. Try to escape.
Try it → Ages 8+ · arithmetic, fixed points card trick ๐Pick a secret card. Follow the counting rule. I never see your choice — and I name your card anyway, about 85% of the time. Learn to perform it.
Try it → Ages 9+ · probability, chains daily ๐ฏSix numbers, one target. Guaranteed solvable, the same for everyone on Earth, brand new every day at midnight. Keep your streak alive.
Play → Ages 8+ · mental arithmeticEverything here is free, permanent and safe to hand to a child: no account, no advertising, no analytics, no cookies, nothing collected. Each page works offline once it has loaded and runs fine on a cheap school laptop or a phone.
Harmonograph and Orbital Sandbox. Pure play — drag, launch, watch. The vocabulary (gravity, orbit, frequency) sneaks in on its own.
Bean Machine and the 3n+1 Mountain. Great for a first real conversation about averages, probability, and what an unsolved problem actually looks like.
Chaos Pendulum, Buffon's Needle and Benford's Law. Energy conservation, Monte Carlo estimation, and how auditors catch invented numbers.
Every page is one plain HTML file with commented JavaScript — no frameworks, no build step. "View Source" is a legitimate lesson plan. Copy it, change it, break it.
Questions, bug reports or an idea for the next game? We'd genuinely like to hear it.