Inside the instrument
How physics instruments measure
Follow a measurement from contact and force to a calibrated number. Explore calipers, precision balances and the Cavendish torsion balance.
How a vernier reads between millimetres
See how a sliding scale and a screw resolve small lengths, then why a checked zero matters as much as fine divisions.
Air helps hold up the object on a balance
Follow a 100 g sample to see how air changes a balance reading and why replacing the sample on the same pan removes an arm-length error.
How Cavendish Measured the Attraction Between Spheres
A soft ribbon catches a tiny gravitational pull. Follow the angle, optical spot and free oscillation that turn it into a measurement.