Lever & Torque Simulator
Adjust the weight and distance on each side and watch the lever respond instantly. It's the same idea behind the popsicle-stick catapult challenge — just without needing rubber bands.
Balanced
Left side
Torque = 4 × 6 = 24
Right side
Torque = 6 × 4 = 24
The math behind it
A lever doesn't balance because the weights on each side are equal — it balances when the torque on each side is equal. Torque is force times distance from the pivot:
torque = weight × distance from pivot
That's why a light weight placed far from the pivot can balance a much heavier weight placed close to it — a 2-unit weight at a distance of 8 produces the same torque (16) as an 8-unit weight at a distance of 2. It's also why a longer lever arm makes it easier to lift something heavy: more distance means more torque from the same amount of force, which is the entire idea behind a wrench, a crowbar, or a catapult's throwing arm.
This simulator is a simplified model — it assumes a massless, rigid beam and ignores friction — the same simplifying assumptions most introductory physics problems make. Real levers have their own weight and flex slightly under load, which is part of why civil and mechanical engineers still have to test physical prototypes even after doing the math.
More on torque as a concept →