• 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. What makes the sound when you pluck a guitar string? (the string vibrating / the string getting hot / the wood breathing / light from the string) → the string vibratingPrompt: Touch the string gently after plucking it.
2. Which state is described: particles packed in a regular pattern? (solid / liquid / gas) → solidPrompt: How close are the particles, and how do they move?
3. Sound: which statement is true? (Loud sounds do not involve vibrations. / Sound cannot travel through water. / Sound travels through space between planets. / Sounds get fainter as you move further from the source.) → Sounds get fainter as you move further from the source.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. Why does sound travel faster in steel than in air? (Steel is shiny / Particles in solids are close together and strongly linked, so vibrations pass on quickly / Air has no particles / Sound is magnetic) → Particles in solids are close together and strongly linked, so vibrations pass on quicklyPrompt: Think about how close particles are.
2. Sound travels at about 5000 m/s in steel. How far does it travel in 0.5 s, in m? → 2500 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. An alarm clock rings inside a jar. As the air is pumped out, the ringing gets quieter. Why? (Air makes sound quieter / Glass absorbs all sound / The clock stops ringing / Sound needs particles to travel through, and there are fewer left) → Sound needs particles to travel through, and there are fewer leftPrompt: Can sound travel through a vacuum?
2. How sound travels: which statement is NOT true? (In a sound wave, air particles travel all the way from the source to your ear. / Whales can communicate over long distances underwater. / Sound waves are longitudinal. / Sound travels faster in water than in air.) → 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.