Teacher sheet · Ages 10–11 · about 45–50 minutes
Sound: vibrations on the move
Lesson page: echoesof.science/school/sound/ages-10-11/ · Pupil worksheet: echoesof.science/school/sound/ages-10-11/print/
Learning aims
- Sound is a vibration that travels as a wave through a medium.
- Sound travels faster in liquids and solids than in air, and not at all in a vacuum.
- Pitch is related to frequency (Hz); loudness is measured in decibels.
- Carry out and compare tests in a simple investigation.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Pluck a ruler on a table edge. What vibrates? What do we hear? |
| 10 min | Read the text. |
| 20 min | String telephones in pairs, filling in the table. |
| 5 min | Compare results: what made the sound clearest? |
| 5 min | Quiz or the Can sound get through? game. |
Materials for the experiment
- Two paper or plastic cups
- About 5–10 m of string
- A sharp pencil (to make the holes, with an adult)
- Two paper clips
Safety: Let an adult make the holes. Don't pull the string near anyone's face, and never shout into the cup when someone is listening.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| Sound travels fastest through air. | It is fastest in solids like steel, then liquids, then gases. |
| There is sound in space; films show explosions with booms. | Space is nearly a vacuum, so sound cannot travel there. |
| Pitch and loudness are the same thing. | Pitch depends on frequency; loudness on how strong the vibrations are (decibels). |
Worksheet answers
- The drum skin vibrates, pushes the air into compressions and rarefactions, the wave travels to the ear and makes the eardrum vibrate.
- Air (343 m/s), water (1480 m/s), steel (5960 m/s).
- Space is nearly a vacuum, so there is no air to carry the sound between their helmets.
- The sound faded or stopped: a slack string cannot pass the vibrations along.
Quiz answers
- What carries a sound wave from a guitar to your ear? Air that is squashed and stretched. Compressions and rarefactions of the air travel outwards.[1]
- In which does sound travel fastest? Steel. Air 343 m/s, water 1480 m/s, steel 5960 m/s.[2]
- Why is space silent? It is almost a vacuum, so nothing can carry the vibrations. Sound needs a medium: a gas, liquid or solid.[5]
- A higher-pitched sound has… a higher frequency. Pitch depends on frequency, measured in hertz.[2]
- About how loud is normal talking? 60 dB. A whisper is about 20 dB, normal talking about 60 dB.[3]
- Why did the string telephone stop working when the string went slack? The slack string could not carry the vibrations. A tight string passes the vibrations along.[1]
Going further
Put your ear to one end of a long table while a partner taps the other end gently. Is it louder through the table or through the air? Why?
Sources used in this lesson
- [1] College Physics 2e, 17.1 Sound (OpenStax, Rice University): reliability High
- [2] College Physics 2e, 17.2 Speed of Sound, Frequency, and Wavelength (OpenStax, Rice University): reliability High
- [3] College Physics 2e AP, 17.3 Sound Intensity and Sound Level (OpenStax, Rice University): reliability High
- [4] The Sound So Loud That It Circled the Earth Four Times (Nautilus (science magazine)): reliability Medium-high
- [5] Data Sonifications (NASA Science): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/sound/sources/
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