Torque & Balance
Hang a mass at a chosen distance from the pivot on each side of a beam, add weight to the beam itself, and shift the pivot off centre — watch the beam swing down on the heavier side and settle, or stay level when the two torques exactly match.
What you can adjust
- Left mass
- 0.5 – 20 kg
- Right mass
- 0.5 – 20 kg
- Left distance from pivot
- 0.2 – 1.5 m
- Right distance from pivot
- 0.2 – 1.5 m
- Beam mass
- 0 – 8 kg
- Pivot offset from beam centre
- -0.5 – 0.5 m
Torque is force times distance from the pivot, not mass alone — more mass here raises this side's torque in direct proportion, the same as sliding it further out would.
Balances against the left side's mass x distance, not against the left mass alone.
A small mass far from the pivot can out-torque a large mass close in — torque only cares about the product of mass and distance.
Same rule as the left side: moving this mass further out increases its torque exactly as much as adding mass would.
The beam's own weight acts at its centre, not at the pivot — with the pivot centred it contributes no torque at all; it only starts to matter once the pivot is off-centre.
Moving the pivot off-centre puts more of the beam's own length — and so more of its weight — on one side, adding a third torque term that can tip the beam even when the two hanging masses' torques are perfectly matched.