Watch gears think.
Four real gear systems, animated and explained. Turn one gear and see exactly how speed, torque and direction move through the whole train.
Why gears look the way they do
Every gear tooth is a small lever. Its size and count decide how fast the next gear turns, how much force it can push with, and which way it spins. Change one number here and watch the whole mechanism respond in real time.
Four mechanisms, one set of rules
Spur & rack-and-pinion
The simplest mesh there is: two toothed wheels, or a wheel rolling along a straight toothed bar.
Planetary gear train
A sun gear, orbiting planets and a ring gear share one axis and produce huge ratios in a small space.
Worm & bevel gears
Two ways to turn motion around a corner: a screw-like worm, or a pair of angled bevel gears.
Compound gear train
Stack several pairs on parallel shafts to multiply ratios far beyond what one pair can do.
Build your own train
The sandbox lets you chain gears together freely and watch the maths update live.
Built for anyone curious about how mechanical power actually moves — no engineering degree required.