• Quick retrieval from earlier learning (Sound comes from vibrations; The particle model). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Rice grains on a drum jump when the drum is hit. What does this show? (The drum skin is vibrating / The drum is magnetic / Sound is made of rice / The rice is alive) → The drum skin is vibratingPrompt: What makes the rice move?
2. Which state is described: particles in fixed positions that only vibrate? (solid / liquid / gas) → solidPrompt: How close are the particles, and how do they move?
3. Sound: which statement is true? (Sound cannot travel through water. / Sound travels through space between planets. / Sound can travel through solids, liquids and gases. / Loud sounds do not involve vibrations.) → Sound can travel through solids, liquids and gases.Prompt: Can sound travel where there is nothing at all?

• Ask the class to make a wave with a rope or slinky and describe what moves and what doesn't.
• Share the objective: How sound travels through solids, liquids and gases. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: Why does sound travel faster in steel than in air?
• Step 1: Sound travels at about 340 m/s in air, 1500 m/s in water and over 5000 m/s in steel.
• Step 2: So the answer is: Particles in solids are close together and strongly linked, so vibrations pass on quickly
• Answer: Particles in solids are close together and strongly linked, so vibrations pass on quickly
• Pause after each step and ask a student to say what comes next.

• Do these together. Students try each step on whiteboards before you reveal it.
• Use the hints as prompts rather than giving the answer.

1. An alarm clock rings inside a jar. As the air is pumped out, the ringing gets quieter. Why? (Glass absorbs all sound / Air makes sound quieter / Sound needs particles to travel through, and there are fewer left / The clock stops ringing) → Sound needs particles to travel through, and there are fewer leftPrompt: Can sound travel through a vacuum?
2. Sound travels at about 1500 m/s in water. How far does it travel in 2 s, in m? → 3000 mPrompt: distance = speed × time

• 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.

• Two questions on their own. Sort answers into got it / nearly / not yet to plan the next lesson.

1. Why does sound travel faster in steel than in air? (Particles in solids are close together and strongly linked, so vibrations pass on quickly / Steel is shiny / Sound is magnetic / Air has no particles) → Particles in solids are close together and strongly linked, so vibrations pass on quicklyPrompt: Think about how close particles are.
2. How sound travels: which statement is NOT true? (Sound travels faster in water than in air. / In a sound wave, air particles travel all the way from the source to your ear. / Sound waves are longitudinal. / Sound cannot travel through a vacuum.) → In a sound wave, air particles travel all the way from the source to your ear.Prompt: Why do we see lightning before we hear thunder?

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-7.