Welcome to practical physicsPracticle physics - practical activities designed for use in the classroom with 11 to 19 year olds

Measuring density

Density is a derived quantity - we measure two other quantities (mass and volume) and then calculate density. A first time learner, however, deserves first to understand the concept - and that takes careful teaching and a little time. Moreover, different techniques are required for solids, liquids and gases.

Many students imagine that a gas such as air has no mass. Carefully 'weighing' air can help students later to answer some startling questions: What's the mass of air in a classroom? The height of the atmosphere? The average speed of air molecules?


Measuring and weighing solid blocks

Measuring the density of regular solid shapes

Weighing liquids

Understanding measuring cylinders

Measuring the density of liquids

Measuring the average density of a student

Weighing a sample of air – a rough estimate

Evacuating a bottle

Weighing air


Related Guidance

Introducing the concept of density

Rough and ready measurements