Working models, built right
Don’t just read the science.
Don’t just read the science.
Build the working model.
125 build-tested projects across five fields. Every page shows the result first, then the materials, the build, and the working principle behind it.
125working models
5categories
25per topic
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Physics
Homopolar Motor
A single AA battery, a magnet and a copper-wire loop spin into the simplest electric motor that actually works.
Easy⏱15 min$3
Chemistry
Lemon Battery Array
Wire lemons with zinc and copper electrodes in series to light a real LED from fruit.
Easy⏱25 min$6
Robotics
Obstacle-Avoiding Robot
An Arduino car reads distance with ultrasonic sound and steers itself away from walls.
Hard⏱3 hr$28
AI
Hand-Drawn Digit Classifier
Train a tiny neural network in the browser to recognise digits you draw with a mouse.
Medium⏱2 hr$0
Environmental
Layered Water Filter
Sand, gravel and charcoal layers visibly clear muddy water — a model of natural and plant filtration.
Easy⏱40 min$5