• Quick retrieval from earlier learning (Pitch and loudness; Parts of a wave). Students answer on mini whiteboards.
• Show answers together and note who needs support in the main task.

1. Which drum makes the lowest sound? (a drum with a very tight skin / a big drum with a loose skin / a small drum with a tight skin / a tiny drum) → a big drum with a loose skinPrompt: Big, loose skins vibrate slowly.
2. Pitch and loudness: which statement is true? (Hitting a drum harder makes a higher note. / Sounds get quieter the further you are from the source. / Loud sounds always have a high pitch. / Longer strings make higher notes.) → Sounds get quieter the further you are from the source.Prompt: Pitch is about how fast; loudness is about how big.
3. Water is poured into identical glass bottles to different levels. You blow across the tops. Which bottle gives the highest note? (they are all the same / the one with the most water (shortest air column) / the empty one / the one with the least water) → the one with the most water (shortest air column)Prompt: When you blow, the air inside vibrates.

• Ask the class to make a wave with a rope or slinky and describe what moves and what doesn't.
• Share the objective: Frequency and amplitude of sound waves. Read the success criteria together.

• Work through the example out loud, saying why you do each step, not just what you do.
• Example: A guitar string vibrates 400 times in 4 seconds. What is the frequency of the sound, in hertz (Hz)?
• Step 1: 400 ÷ 4 = 100
• Step 2: So the answer is: 100 Hz
• Answer: 100 Hz
• 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. A guitar string vibrates 600 times in 3 seconds. What is the frequency of the sound, in hertz (Hz)? → 200 HzPrompt: Frequency is the number of waves (vibrations) per second.
2. A dog whistle produces sound at 2 kHz. What is this frequency in Hz? (1 kHz = 1000 Hz) → 2000 HzPrompt: “kilo” means one thousand.

• 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 the upper limit of hearing often fall as people get older? (Older people make higher sounds / Sound gets slower / Sensitive cells in the inner ear are gradually damaged / The ear canal gets wider) → Sensitive cells in the inner ear are gradually damagedPrompt: Loud noise speeds this up.
2. Humans can hear from about 20 Hz to 20 000 Hz. Could a young person hear a sound of 2 kHz? (yes / no, it is ultrasound) → yesPrompt: Convert kHz to Hz first.

Free online practice with hints and printable worksheets for this skill: eurekami.com/science/grade-6.