Practical method: density

What you will learn

• Use density = mass divided by volume.
• Measure volume for regular and irregular solids.
• Measure liquid density using mass difference and volume.
• Explain uncertainty and zero-error checks in density practicals.

Density practical data supplied on this page

Use the cuboid, stone and liquid examples to practise choosing the right volume method before calculating density.

Density practical method infographic

Clear explanation

Density tells you how much mass there is in each unit volume. The equation is density = mass ÷ volume.

For a regular solid, measure length, width and height, then calculate volume. For an irregular solid, use water displacement and read the change in water volume.

For a liquid, measure the mass of an empty container, then the mass of the container with liquid, and subtract to find the liquid mass.

Key diagram

Worked examples

Quick checks

Choose an answer, then check your thinking.

Practice questions

Practice ladder

Answers and marking guidance

The exact practice answers are hidden under each question so you can try first. For this lesson, marks come from using the correct physics model, choosing the right equation where needed, keeping units with values, and explaining changes with precise words such as transfer, resultant force, acceleration, evidence and uncertainty.

Common mistakes

• Using volume divided by mass.
• Forgetting to subtract the empty container mass.
• Reading the measuring cylinder from above or below the meniscus.
• Mixing cm3 and m3 without converting.

Extension challenge

Compare two methods for measuring the volume of an irregular solid and explain which has lower uncertainty.

Exam-board guidance

Short board notes only. Learn the core physics above first.

Next lesson

Next, continue with Terminal Velocity and Free-Body Diagrams.