Science lesson plan · 7th grade (Year 8 in England) · 60 minutes
Density
States of matter
CCSS NGSS.MS-PS1-2CCSS NGSS.5-PS1-3England: KS3 Physics: MatterEngland: KS4 Combined Science: Particle model of matter
Objective and success criteria
Students will: Density.
- I can answer questions on today's skill on my own, without help.
- I can explain each step and say why it works.
- I can check my answer and spot a mistake.
Before and after
Needs first: The particle model
Leads to: Find density using water displacement
Materials: Ice, water and a kettle (teacher demo), Particle diagrams, Mini whiteboards, A diagram or short video clip of the idea, Printed student sheet (below).
Warm-up · 6 min
- Quick retrieval from earlier learning (The particle model). Students answer on mini whiteboards.
- Show answers together and note who needs support in the main task.
- Which state is described: particles far apart moving quickly in all directions? (solid / liquid / gas) → gasPrompt: How close are the particles, and how do they move?
- What happens to particles when a substance is heated? (They move faster / They get bigger / They stop moving / They melt) → They move fasterPrompt: Heating gives particles more energy.
- The particle model: which statement is NOT true? (There is empty space between gas particles. / Particles expand when they are heated. / Particles in a gas are much further apart than in a liquid. / Particles in a solid still vibrate.) → Particles expand when they are heated.Prompt: Do particles themselves change size?
Hook · 6 min
- Show an ice cube melting and a kettle steaming and ask what is the same and what is different.
- Share the objective: Density. Read the success criteria together.
I do: model it · 12 min
- Work through the example out loud, saying why you do each step, not just what you do.
- Example: A block has a mass of 27 g and a volume of 10 cm³. What is its density, in g/cm³?
- Step 1: density = mass ÷ volume
- Step 2: 27 ÷ 10 = 2.7
- Step 3: So the answer is: 2.7 g/cm³
- Answer: 2.7 g/cm³
- Pause after each step and ask a student to say what comes next.
We do: guided practice · 12 min
- Do these together. Students try each step on whiteboards before you reveal it.
- Use the hints as prompts rather than giving the answer.
- A block has a mass of 62.5 g and a volume of 25 cm³. What is its density, in g/cm³? → 2.5 g/cm³Prompt: density = mass ÷ volume
- The density of glass is 2.5 g/cm³. Water's density is 1.0 g/cm³. Does a solid piece of glass float or sink in water? (floats / sinks) → sinksPrompt: Compare the density with water's density.
You do: independent practice · 17 min
- Students work on the student sheet. Circulate and check the first two answers of every student early.
- Students who finish: write a question of their own for a partner, with the answer.
The 8 questions are on the student sheet below, with answers in the key.
Exit ticket · 7 min
- Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.
- The density of rubber is 1.1 g/cm³. Water's density is 1.0 g/cm³. Does a solid piece of rubber float or sink in water? (floats / sinks) → sinksPrompt: Compare the density with water's density.
- A block has a mass of 17.8 g and a volume of 2 cm³. What is its density, in g/cm³? → 8.9 g/cm³Prompt: density = mass ÷ volume
Watch out for
- Everyday meanings of words getting in the way of the science meaning: define key words explicitly.
- Remembering facts without the reason: ask "why?" and "what is the evidence?"
Support and stretch
Support
- Review first: The particle model.
- Use concrete materials: ice, water and a kettle (teacher demo).
- Give the first step of each question, or a partly worked example to finish.
- Pair with a confident partner for the guided practice.
Stretch
- Move on to: Find density using water displacement.
- Explain a common mistake in writing and how to fix it.
- Write a word problem that uses today's skill, then solve a partner's.
Homework and more practice
Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-7.
Free lesson plan from eurekami.com/lesson-plan-builder