Density: Mass, Volume and Floating
A comprehensive physics lesson for Year 9 exploring the property of density. The lesson covers the mathematical relationship between mass and volume, particle theory, and the practical methods for measuring the density of irregular objects.
Learning objectives
- Define density and state its standard units (kg/m³ and g/cm³).
- Calculate density, mass, and volume using the formula: Density = Mass / Volume.
- Describe how to determine the density of regular and irregular solids using displacement.
- Explain floating and sinking in terms of density relative to a fluid.
Lesson plan (60 minutes)
Introduction · 5 min
Retrieval starter: Defining mass and volume and simple unit conversions.
Direct Instruction · 15 min
Teacher-led instruction: Explaining the density formula, particle arrangements, and the required practical method.
Independent Practice · 25 min
Differentiated worksheet task: Students work through Support, Core, or Stretch questions based on prior attainment.
Feedback · 5 min
Peer marking and review of worked examples on the board.
Plenary · 10 min
8-question MCQ quiz to check for understanding and address misconceptions.
Key vocabulary
- Mass
- The amount of matter in an object, measured in grams (g) or kilograms (kg).
- Volume
- The amount of 3D space an object takes up, measured in cm³ or m³.
- Density
- The mass per unit volume of a substance.
- Displacement
- When an object moves water out of the way to make room for itself.
- Eureka Can
- A container with a spout used to measure the volume of irregular objects.
Core worksheet (first questions)
- Define density and state the formula used to calculate it.
- Give two different units used for density.
- A metal cube has a mass of 200g and a volume of 100cm³. Calculate its density.
- An irregular stone is dropped into a measuring cylinder containing 30cm³ of water. The water level rises to 50cm³. The stone has a mass of 160g. Calculate the density of the stone.
Quiz (sample)
1. What is the formula for density?
- A. Mass times volume
- B. Volume divided by mass
- C. Mass divided by volume
- D. Mass plus volume
2. Which of these is a standard unit for density?
- A. g/cm³
- B. kg/m
- C. N/cm²
- D. kg/cm
3. What is the approximate density of pure water?
- A. 0.1 g/cm³
- B. 1.0 g/cm³
- C. 10 g/cm³
- D. 100 g/cm³
The full pack is waiting
Support and Stretch worksheets, every answer and model answer, the teaching explainer and common misconceptions, editable and ready to print as PDF or Word.
Start your 14-day trial