---
title: "How physics instruments measure"
description: "Follow a measurement from contact and force to a calibrated number. Explore length, mass, gravity, pressure, heat and viscosity."
canonical_url: "https://sandboxphysics.com/stories/instruments/"
language: "en"
page_type: "lab-directory"
alternate_languages:
  zh-CN: "https://sandboxphysics.com/zh/stories/instruments/"
last_modified: "2026-10-28"
---

Inside the instrument

# How physics instruments measure

Follow a measurement from contact and force to a calibrated number. Explore length, mass, gravity, pressure, heat and viscosity.

[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.](https://sandboxphysics.com/stories/instruments/length-metrology/) [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.](https://sandboxphysics.com/stories/instruments/precision-balance/) [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.](https://sandboxphysics.com/stories/instruments/cavendish-balance/) [Which pressure does a liquid column measure? Follow a U-tube height reading from gauge pressure to absolute pressure. Compare an open end, a trapped gas and a vacuum reference.](https://sandboxphysics.com/stories/instruments/manometer/) [The cup absorbs heat too A calorimeter connects electrical energy with warming. A water-only blank removes the cup’s contribution, and the cooling tail reveals heat loss.](https://sandboxphysics.com/stories/instruments/calorimeter/) [Does a harder turn mean a thicker liquid? How a rotational rheometer turns torque into viscosity, and why rising torque can accompany shear thinning.](https://sandboxphysics.com/stories/instruments/rotational-rheometer/)