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Year 7

Travelling vibrations

I can explain how vibrations are passed to and through the air, to allow sounds to be heard.

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New
New
Year 7

Travelling vibrations

I can explain how vibrations are passed to and through the air, to allow sounds to be heard.

Download all resources
Share activities with pupils

Lesson details

Key learning points

  1. A vibrating object causes nearby air particles to vibrate too.
  2. Air particles are knocked forwards but then spread backwards when the object moves back.
  3. Vibrating air particles knock into their neighbours and set them vibrating too, in the same way.
  4. The pattern of vibrating particles creates a sound wave. Sound does not involve air particles travelling.
  5. Scientific models often only accurately reflect some aspects of what they represent.

Common misconception

Pupils can think that sound is a material substance, or involves particles of some kind (e.g. of air, or 'of sound') travelling or being blown out from a source.

Spend time exploring and modelling how vibrating objects set particles vibrating, how vibrating particles will collide into neighbouring particles to set them vibrating too, and how patterns of vibrations produce the 'pulses' of a sound wave.

Keywords

  • Particle - What solids, liquids and gases are made up from.

  • Vibrate - To regularly and repeatedly move back and forth.

  • Scientific model - Any way of accurately representing, picturing or imagining a scientific idea.

  • Wave - A disturbance that travels, like a ripple on water.

An 'airzooka' or 'air vortex cannon' may provide an engaging and memorable way to demonstrate ideas in this lesson, if available. You could consider demonstrating a speaker. The model of sound in Task C could be built to demonstrate. There are excellent (additional) animations of sound waves online.
Teacher tip

Equipment

Loudspeaker, signal generator/sound input, candle (to provide a demonstration of Task B – optional but will add engagement – check it works as anticipated first).

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Video

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Starter quiz

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6 Questions

Q1.
Which of the following actions are vibrations?
repeated growing and shrinking
Correct answer: repeated movements up and down
Correct answer: repeated movements left and right
Correct answer: repeated movements forwards and backwards
Q2.
Three things that can make sounds are: a human speaking, a flute and a violin. How many of these cause sounds by making something vibrate?
none of them
one
two
Correct answer: three
Q3.
Match each of the following key terms with its definition.
Correct Answer:volume,the loudness of a sound

the loudness of a sound

Correct Answer:pitch,how high or low a note is

how high or low a note is

Correct Answer:amplitude,the size of a vibration (how far an object vibrates)

the size of a vibration (how far an object vibrates)

Correct Answer:frequency,the number of vibrations per second

the number of vibrations per second

Q4.
Which of the following changes will lower the pitch of the sound made by a drum?
Correct answer: Make the drum skin less tight.
Use a smaller drum.
Hit the drum more softly.
Q5.
If the of the vibration of an object increases, the pitch of the sound it makes also increases.
Correct Answer: frequency, frequencies
Q6.
If the of a vibration of an object increases, this increases the volume of the sound it makes.
Correct Answer: amplitude, amplitudes

Exit quiz

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6 Questions

Q1.
Which of the following is a description of a wave?
Correct answer: a travelling disturbance
a collection of particles
an amount of energy
Q2.
A vibrating ruler makes a sound. Each time the ruler moves forwards, it pushes air particles forwards. What do these particles do to make the sound travel forwards across the room?
They travel to the other side of the room.
Correct answer: They hit air particles in front of them.
They pull on other air particles that are joined to them.
They stick to air particles in front of them.
Q3.
Sort the following statements into the correct order to describe what happens to particles that are near the left side of the string when a guitar string is plucked and starts vibrating.
1 - The string hits nearby air particles.
2 - This pushes them in the same direction as the string is moving.
3 - This makes them get closer together.
4 - When the string moves the opposite way, this creates empty space.
5 - Some nearby air particles move into the space because of their random motion.
Q4.
Which of the following explains how a person can hear a sound?
The sound wave makes air build up inside the ear.
Correct answer: The sound wave makes part of the ear move back and forth.
The sound wave warms and cools the ear.
Q5.
A scientific model is about a part or behaviour of the real world.
an exact description
a picture we can draw
a good guess we can make
Correct answer: a helpful but not always accurate way of thinking
a 3D model we can make (with clay, for example)
Q6.
In a simple model of a sound wave in air, air particles simply move back and forth. The wave travels because particles hit other particles. Which of the following details does this model ignore?
the fact that air is a gas
Correct answer: the random motions of the air particles
the back and forth vibrations of the air particles
Correct answer: the different types of air particle