Sound waves and hearing
Sound needs particles to travel through, while light can cross empty space — two very different waves that both let us sense the world.
Part of your national curriculum
- Physics: waves: Understand the similarities and differences between light waves and waves in matter, and frequencies of sound waves measured in hertz
Lesson overview
What you'll learn in this lesson
Understand the similarities and differences between light waves and waves in matter, and frequencies of sound waves measured in hertz
Key learning points
- • Sound is a wave in matter
- • Frequency and hertz
- • Comparing light and sound waves
This lesson at a glance
- 24 minutes
- 14 parts to scroll through
- 3 quick checks
- Marked quiz at the end
- Gentle pace: short sittings with pauses
Words to know
Scroll down — the lesson carries on below
Watch & discover
Part 1 of 14
Watch first
Sound waves and hearing
An English teaching video on this topic from Lammas Science. Watch it, then scroll down for the lesson.
In a nutshell
Understand the similarities and differences between light waves and waves in matter, and frequencies of sound waves measured in hertz
Learning cycle
Part 2 of 14
Learning cycle 1 of 2
Part 1 · Sound is a wave in matter
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 3 of 14
Learn
Sound is a wave in matter
Sound is a longitudinal wave caused by vibrations, travelling through solids, liquids and gases as particles bump into their neighbours, passing energy along. Because it needs particles, sound cannot travel through a vacuum, unlike light.
Explore the idea
Part 4 of 14
Learn
Frequency and hertz
Frequency is the number of wave vibrations per second, measured in hertz (Hz). Higher frequency sounds are heard as higher pitch. Humans typically hear frequencies from about 20 Hz to 20,000 Hz (20 kHz); sounds above this range are ultrasound.
Quick check
Part 5 of 14
Quick check
Why can't sound travel through a vacuum?
Reset break
Part 6 of 14
Pause
That's sitting 1 of 2 done
Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.
Quick check
Part 7 of 14
Quick check
What is measured in hertz (Hz)?
Learning cycle
Part 8 of 14
Learning cycle 2 of 2
Part 2 · Comparing light and sound waves
A short piece of teaching, then a check to make sure it has landed.
Explore the idea
Part 9 of 14
Learn
Comparing light and sound waves
Light is a transverse wave that can travel through a vacuum at very high speed (about 300,000 km/s), while sound is a longitudinal wave that needs a medium and travels far slower (about 340 m/s in air). Both waves transfer energy without transferring matter.
Quick check
Part 10 of 14
Quick check
Approximately what is the upper limit of human hearing?
Challenge round
Part 11 of 14
Game · Sort it
Which of these are true?
Drag each card into the right column. Tap a card first if dragging is fiddly.
True
Not true
Challenge round
Part 12 of 14
Game · Fill the gaps
Finish the sentences
Choose the word that belongs in each gap.
Frequency is the number of wave vibrations per second, ____ in hertz (Hz).
Humans typically hear ____ from about 20 Hz to 20,000 Hz (20 kHz); sounds above this range are ultrasound.
Both waves transfer energy without transferring ____.
Mastery quiz
Part 13 of 14
Marked quiz
End of lesson quiz: Sound waves and hearing
3 questions, marked with the reasoning shown. No timer.
1. Why can't sound travel through a vacuum?
2. What is measured in hertz (Hz)?
3. Approximately what is the upper limit of human hearing?
Lesson round-up
Part 14 of 14
Lesson round-up
Ready when you are
Quiz score
Not sat
Games
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Points this lesson
0
Best run
0 in a row
Luna: 0 out of 3 on the practice checks. Only if you feel up to it — one more?
Ask LunaDo the work
Your written work for this lesson
This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.
Why the school greenhouse failed
A science club grew tomato plants in the school greenhouse. In June the plants grew well: leaves were dark green and the fruit set quickly. In July the club went away for two weeks and left the greenhouse door shut. When they came back, the leaves were curled and pale and most of the fruit had dropped.
The club had a data logger inside. It showed the temperature reached 46 °C on several afternoons and the soil moisture fell close to zero. The club knew photosynthesis needs light, water and carbon dioxide, and that enzymes in a plant work best in a narrow range of temperature. Above that range the enzymes stop working properly.
The club repeated the summer with the door propped open and a water bottle drip on each pot. Temperature peaked at 31 °C and the plants survived.
Written for Good Learning Co.
Reading questions
- Name the variable the club changed the second time, and one variable they kept the same.
- Explain, using the words photosynthesis and enzymes, why the plants were damaged in July.
- Write a conclusion for the club's report, saying how far the evidence supports it.
Method and results
WritingWrite the aim, what you changed, what you measured and what you kept the same, then record your results in a table.
1 page + results table
Conclusion
WritingExplain what your results show and why, using the scientific words from the lesson. Say how you know you can trust them.
6–8 sentences
Labelled diagram
DiagramDraw the apparatus or the process in pencil, label it fully, and photograph it.
1 labelled diagram
Reading and notes
ReadingRead the lesson text again and write the key ideas in your own words.
Half a page of notes
Saved as you type.
Part 1 of 14 · Watch & discover
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Understand the similarities and differences between light waves and waves in matter, and frequencies of sound waves measured in hertz