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
- 17 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 17
Visual introductionPicture this
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.
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 17
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 17
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.
Reset break
Part 4 of 17
Pause
That's sitting 1 of 4 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.
Explore the idea
Part 5 of 17
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 6 of 17
Quick check
Part 7 of 17
Reset break
Part 8 of 17
Pause
That's sitting 2 of 4 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.
Learning cycle
Part 9 of 17
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 10 of 17
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 11 of 17
Reset break
Part 12 of 17
Pause
That's sitting 3 of 4 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.
Challenge round
Part 13 of 17
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 14 of 17
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 ____.
Challenge round
Part 15 of 17
Game · Recall cards
Why can't sound travel through a vacuum?
Card 1 of 3
Mastery quiz
Part 16 of 17
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 17 of 17
Lesson round-up
Ready when you are
Quiz score
Not sat
Games
Not played
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 LunaPart 1 of 17 · Watch & discover
How this is going
- Not looked at yet
Understand the similarities and differences between light waves and waves in matter, and frequencies of sound waves measured in hertz