A curious child turns two connected gears; the small output winds a rope attached to a heavy crate resting on the floor.

Can a tiny fast gear lift a heavy crate?

tap the fast little gear

The little gear whirls when the crank turns. Its spool and rope lead to a crate resting on the floor. The fast spin is easy to see. What will happen when the crate pushes back?

first, zoom in

One meeting point controls both wheels

Each amber tooth meets one teal tooth. Neither wheel can skip ahead at the contact.

where the push acts matters

Try a longer handle

handle length1 step from axle
short handlelong handle

Twice as far out gives twice the twist—and twice the hand travel. A rope pulls back too: a wider drum makes the same load resist with more twist.

count what passes

Tap one tooth-step at a time

One amber tooth passes; one teal tooth passes. The counts stay matched.

change one thing

Fewer teeth means more turns

teal output18 teeth · 1 turn per crank
6 teeth36 teeth

The teeth share the same contact push. On a bigger output, that push acts farther from its axle: more twist, but fewer turns.

drive the fast pair

One crank turn makes three output turns

move the crank0 crank · 0 output turns
startone crank turn

The rope drum turns with the output axle. The next test changes both the gear and its drum.

two changes at once

A bigger gear… and a wider drum

Same crank handles and crates. The right output gear has twice as many teeth. Its rope drum is also twice as wide.

Which needs less hand push to start the same crate?

Same crank and crate. Bigger gear AND wider drum.

Which machine needs less hand push to start lifting?