• 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 big drum with a loose skin / a drum with a very tight 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? (Longer strings make higher notes. / Hitting a drum harder makes a higher note. / Faster vibrations make higher-pitched sounds. / Loud sounds always have a high pitch.) → Faster vibrations make higher-pitched sounds.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 least water / the empty one / the one with the most water (shortest air column)) → 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 1500 times in 3 seconds. What is the frequency of the sound, in hertz (Hz)? → 500 HzPrompt: Frequency is the number of waves (vibrations) per second.
2. Humans can hear from about 20 Hz to 20 000 Hz. Could a young person hear a sound of 25 kHz? (yes / no, it is ultrasound) → no, it is ultrasoundPrompt: Convert kHz to Hz first.

• 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 6 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. A guitar string vibrates 512 times in 2 seconds. What is the frequency of the sound, in hertz (Hz)? → 256 HzPrompt: Frequency is the number of waves (vibrations) per second.
2. Two sound waves are shown on an oscilloscope. Wave B has taller peaks than wave A but the same spacing. How does B sound? (louder, with the same pitch / lower pitched / higher pitched / quieter) → louder, with the same pitchPrompt: Taller waves have a larger amplitude.

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