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

• 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 1280 times in 5 seconds. What is the frequency of the sound, in hertz (Hz)? → 256 HzPrompt: Frequency is the number of waves (vibrations) per second.
2. A dog whistle produces sound at 15 kHz. What is this frequency in Hz? (1 kHz = 1000 Hz) → 15000 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. A guitar string vibrates 125 times in 0.5 seconds. What is the frequency of the sound, in hertz (Hz)? → 250 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 5 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.