Pulley Lifter
by ArcadeLabA pulley sandbox that lets kids feel mechanical advantage. Thread the rope through 1, 2, or 3 pulleys, then drag the rope handle to hoist a heavy crate. With one pulley the pull is hard; add pulleys and the pull gets easier — but you have to pull that much more rope. Live effort and rope-length meters make the trade-off obvious: pulleys don't create free energy, they swap a long easy pull for a short hard one.
Frequently asked
How does a pulley make lifting easier?
A pulley system shares the weight of a load across several strands of rope. With two supporting strands you only pull half the weight, with three strands a third. The catch is that you must pull the rope two or three times as far.
What is mechanical advantage?
Mechanical advantage is how much a machine multiplies your force. A 3-pulley system has a mechanical advantage of about 3 — you push with one-third the force, but over three times the distance. Total work stays the same.
Why do you pull more rope with more pulleys?
Energy is conserved. Lifting a crate one meter takes the same amount of work no matter what. If the machine cuts your force to a third, it has to make up for it by having you pull three times as much rope.