Claw Game Maker
Everyone has lost a bear to a claw machine and called it rigged. Claw Game Maker lets students build the machine themselves: the box, the claw, how hard it squeezes on the grab, the lift and the carry, and what goes in the pile. Then they play it with real physics, watch the replay with the forces drawn on, and learn exactly why the bear slipped. Then they make it fair.
Using this with a class? Make a free class and add your students yourself: each gets a username and password, with no email or Google account needed. Or give them one join code. Using Google Classroom? Post the link there; with a free class, the link also puts each student in your class, so you see their work. mytekDev is also available from the Google Workspace Marketplace, so your school's Google admin can install it for everyone.A first lesson: One period: play the starter three times, read why each prize dropped, find a bear's holding grip on the Grip Bench and compare it with its weight and friction, then send twenty robot players at the machine and compare their win rate with a prediction. A second period to build and share a fair machine of their own.
Set up a free class Share to Google ClassroomWhat a student actually does
The screen is a claw machine in a room, seen the way a player sees it, with a side view for lining up the depth. Play steers the claw with the arrows or a pad, Drop sends it down, and the claw closes, lifts, carries whatever it caught to the chute and lets go. Nothing is decided in advance: the prongs are hinged bodies closed by motors whose force limit is the grip setting, and friction between the tips and the prize is what holds it up. When the card says Missed, Why did it drop? plays the grab again with arrows for weight, push and friction and one sentence on what went wrong: never lifted, slipped off one side, tipped out, let go when the grip eased off at the top, or stuck across the chute.
Build is the operator's side. The Cabinet sub-tab sets the box, the chute and its lip, the colors, the sign and the lighting inside. The Claw sub-tab sets how many prongs, their length, the tip curl, the pad angle and how wide it opens, the tips (rubber, plastic or bare metal), the three grips in newtons for the grab, the lift and the carry, and the speeds and timer. The Prizes sub-tab fills the box with bears, ducks, capsule balls, boxed toys, keychains and mini bears at real masses, or a 3D model of the student's own from the library. Every slider changes the machine as it moves.
Test is the lab. The Grip Bench puts one prize under the claw at a chosen grip and reports whether it held, with the push and the friction the tips made. Robot players play the machine twenty times with a set aim error and report the win rate, next to the student's prediction. Before a machine can be shared, it must pass the honest machine check: the maker has won a prize from it, and every prize kind in it can be lifted at the machine's own grips, the way several states require that every prize on show be winnable.
Why did it drop? plays the last few seconds again at quarter speed with the forces drawn on: weight, the push from each prong, and the friction that push could make. The sentence is written from what the physics recorded, not from a script.
What they are learning while they work
Nothing here is presented as a lesson. This is what the activity is made of.
| What the student does | What it is |
|---|---|
| Turns the grip down until the bear slides out | Friction holds the prize, and friction has a limit. The prongs squeeze sideways; friction turns that squeeze into an upward hold. A 180 g bear weighs 1.8 N. Three rubber tips on plush can hold it by squeezing alone only above about 0.8 N each, and in practice the bear needs a little more. |
| Finds that a capsule ball holds at a far lower grip than its friction says | Cradling is not squeezing. Curled tips close under a round prize and carry it on their shape, so it holds with almost no squeeze. Hooked pads cradle a bear too. Straight tips can only squeeze. |
| Reads the replay of a bear held by one leg | Torque: a grab off the middle turns the prize. Weight acts at the center of mass. Held off to one side, the prize turns about the prongs, and the farther from the middle, the bigger the turning push. |
| Sets the carry grip lower than the grab | The operator menu is real. Real machines are often set to squeeze hard on the grab and ease off on the way to the chute, which is why prizes fall mid-air. The app lets a student build that machine, and the honest check tells them what it means. |
| Swaps bare metal tips for rubber pads | Materials change friction. Each surface has a number for how grippy it is; a pair of surfaces averages the two. Rubber on plush is about 0.7, bare metal on hard plastic about 0.3, so the same grip holds very different prizes. |
| Runs twenty robot players and compares the win rate with a guess | Probability from repeated trials. The robots aim with a set wobble, so the win rate is a property of the machine and the pile. Twenty plays give a rough rate; the pile's luck shows up as a spread between seeds. |
| Builds a machine that passes the honest check and is still fun | Engineering design under a constraint. Every prize must be winnable at the machine's own grips, and the maker must have won one. Students iterate: grips, tips, prong shape, the pile, until it passes and plays well. |
How to tell whether it landed
Ask, and let them show you. A student who has understood it can answer these without help.
- The claw squeezes sideways. What holds the prize up, and what sets the limit on that?
- A capsule ball holds at a grip far below what its friction line says. How?
- Why does a bear held by one leg turn and slide out?
- A real machine is set to grip hard on the grab and ease off on the carry. What does that do, and why would an operator set it that way?
- Twenty robots won 7 times. What would you expect from the next twenty, and why might it differ?
- What does it take for a machine to pass the honest check, and why do some states require it?
Use it in your subject
Not a technology class? Then the app is how students show what they learned in your unit. More projects for every subject.
Middle school physical science
MS-PS2-2: the motion of a prize depends on the forces on it and its mass. One variable at a time on the Grip Bench: the grip, or the mass, or the tip material, and whether the prize held.
Middle school engineering
MS-ETS1-1 to 4: build a claw machine that is fun and fair, test it with a model that generates data (the robot players), and iterate. The honest machine check is the constraint.
Grade 7 math
7.SP.C.6 and 7: the win rate from repeated plays, a prediction before the run, and why twenty plays and two hundred plays disagree.
High school physics
The same machine with the numbers on: the friction line from weight and the coefficient, the three-stage grip, torque from a grab off the center of mass, and the simplifications stated.
Makerspace and after school
Build, play, share, and play one another's machines. Students who have lost money to a real claw machine have questions, and this answers them.
Practical notes
- AgesGrades 6 to 8 are the home ground: the Kid level speaks in weak, medium and strong grips and plain sentences; Middle school shows the newtons; High school adds the friction line, the torque and the formulas. Younger students can play and build without the Test tab.
- TimeOne period for the first plays, the Grip Bench and the robots. A second to build and share a fair machine. The puzzles fill a third.
- EquipmentA computer or Chromebook with a modern browser and WebGL. Nothing to install. A projector for Big screen.
- CostFree. The app has no paid tier.
- PrepPlay the starter three times and press Why did it drop? once, about five minutes. That is the whole demo.
- In a groupOpen Setup in the app's header: the level, which tabs students can open, whether the level is locked, the sheet's questions and up to ten of your own, and a printed answer key.
For co-ops, microschools, and classrooms
Set it up once in Setup and hand the project out as the starter; the machine, the tabs and the questions travel with it. With a free account the students' sheets come back to you as saved projects, with their predictions, their bench rows, their robot runs and whether their machine passed the honest check. Shared machines can be played by classmates from the share page.
Common questions
Is it free?
Yes. Claw Game Maker has no paid tier, and it can be tried right on this page without an account.
Is the physics real?
The claw, the prizes and the box are rigid bodies in a physics engine. Each prong is a hinged body closed by a motor whose force limit is the grip, so a prize that pushes back harder than the motor can pull makes the prong give, and friction at the tips is what holds it up. Nothing is attached to anything, and no play is decided ahead of time.
What does it simplify?
The prizes are stiff; real plush squashes and the prongs sink in, which helps a grab. Friction is one typical number per surface, averaged for each pair, where real friction belongs to a pair and is measured; on soft materials it is not one fixed number. The friction the replay draws is what the contact could have made at that push, and whether the prize held is what the physics decided. How it works in the app says all this.
Does it teach that claw machines are rigged?
It teaches what the operator can set. A real machine's menu does let the grip ease off on the carry, and the app lets a student build one that way. It also lets them build a fair one, and it will not let a machine be shared until every prize in it can be lifted at its own grips.
Can students use their own 3D models?
Yes. Any .glb from the platform's library or a student's own files becomes a prize. The app builds its convex hull once, which is what the claw grabs, and draws a coarse copy of a detailed model so the pile stays smooth.
What about privacy?
A machine's name, its sign, sheet answers and the names of a student's own models are text, and they pass through the platform's word filter on the share page like every other app. The app reads no location and no camera.
Where did claw machines come from?
Crane games began in the 1920s and 1930s as diggers, little steam shovels in a glass case that scooped candy. Japan's two-button machines of the 1980s made them a game of skill, and US states treat a crane as an amusement or a gambling device depending on whether skill decides the result. The app's Two buttons stick is that Japanese style.
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Where to go next
Badge kits and learning kits
Step-by-step projects in Claw Game Maker that end with a certificate: for a scout badge, or for homeschool families and classes.
- Make a Fair Claw Machine: Learning kit badge, or the learning kit for grades 6-8
Lesson plans
4 ready-to-teach class periods with a teacher plan, a student worksheet, an exit ticket with answers, and the standards it meets.
Start with Claw Game Maker
Trying it costs nothing and takes about five minutes. An account is what makes the work last.
Claw Game Maker is one of the making apps on the platform. The physics is Rapier; the picture is three.js. Prize masses come from operator guides for standard and mini cranes; the friction numbers are typical values for each surface.
Page last reviewed November 2026.
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