Sound
From musical boxes to iPods
Supports National Curriculum, Key Stage 1: Unit 1F and Key Stage 2: Units 5F
Suitable for years 4,5 and 6.
The time for the basic session is about 1 hour but longer if activities 13,16,17,18, 22 are included. This can be varied by taking shorter paths through the material. Choices may depend on the apparatus available or the particular needs of the class.
Outline of content
Aims to
- establish what the children already know, using an intriguing demonstration
- establish that sounds needs a material through which to travel
- show that vibrating objects are sources of sound and sound travels as a wave
- demonstrate that sound can travel through metal, string, etc as well as air
- associate the size of the vibrating object with the frequency produced through fun pictures, activities and wind instruments
- relate their knowledge to other instruments with which they are familiar
- show that knowledge about sound has enabled scientists to develop ultrasound scans, modern sound systems etc
Points to note:
Please read the notes about safety and agree the assessment with the teacher before the session!
Cross References
- The slides in the PowerPoint presentation are referenced in the table.
- As the presentation may be running throughout the session some simple slides provide a suitable background, alternatively switch to a black screen.
- Apparatus details are provided and are linked to the relevant sections.
- Notes about safety are included at the end of the document
Vocabulary: The presentation uses expressions included in the KS 1&2 strategies http://www.standards.dfes.gov.uk/schemes2/science/?view=get
Misconceptions to be corrected
Air moves with the sound from the source to our ears.
Sound can only travel through air.
Sound is like light in that it cannot travel through opaque objects.
When blowing a bottle - the more water the lower the pitch.
The strings on violins etc are at very different tensions eg they expect the E string on a violin to be at a much higher tension than the G string.
Feedback from the trials:
“Thanks for the lesson on sound - the children loved it and were talking about it the next day - a good topic to teach due to the children's interest in sound.”
“They 'loved' the graphics on screen of the animals and examples of musical equipment. They were fascinated by the practical demonstrations, which I personally believe is how children learn and acquire more knowledge more effectively.”
“The children listened intently throughout and were very responsive.
I thought the lesson was conducted excellently and the children were enthralled. The information provided was suited to the children’s learning ability (this is important).”
Sound
From musical boxes to iPods
Activity / Discussion / Aims/factsShow Powerpoint Slide 1 should be showing as the class enters. (Some cheerful music could be playing - if this is convenient - switch it off before starting.)
1. Demonstration
Hold up the drive mechanism of a musical box which is playing.
Then touch the mechanism on a metal tray or metal tray.
See Apparatus List / As you hold up the mechanism, ask what the children can hear. Only a few close to the front will hear anything.
Once the mechanism is held against the tray the tune should then be heard loudly. Ask them to try to explain. / To catch the children’s attention and find out what they know.
2. Discussion / Ask how they hear the sound.
Discuss the sound being produced and then travelling to their ears. / Sound travels from a source to their ears.
3. Show Powerpoint Slides 2,3,4
Explain that sometimes astronauts have to climb outside their spacecraft to make repairs. Point out that the earth can be seen so far away that the curvature of the horizon is clear.
In slide 3 the space ship is reflected in the astronaut’s visor. / Point out that if someone shouts outside a house, the sound can be heard inside the house. Space ships have very thin outer skins. Ask whether, during a space walk, an astronaut could be heard by those inside the space craft. If they are not sure, point out that some of the pictures show the astronaut attached to a line. Ask what it is for. (For Communications and to prevent the astronaut moving away from the space ship and being lost.) / There is no air outside the space craft so the astronaut’s calls would not be heard by those inside the space craft.
Sound needs something to travel through.
(eg air )
4. Demonstration
Show Powerpoint Slide 5
Use an Airzooker to send a waft of air across the classroom to blow the hair of some of the children.
See Apparatus List
See Safety Notes / Point out that there is air in the classroom and they can hear you speaking. Then ask the children whether they feel a rush of air when you speak.
They will enjoy this and understand that sound does not travel with the air.
Explain that there must be another explanation. / Conclude that air does not travel with the sound.
5. Class activity: ‘dance’
Ask about 10 volunteers to line up across the classroom all facing towards one end of the line. Child 1 should start to step. The as soon as child 2 sees child 1 move, 2 should start to step. As soon as child 3 sees child 2 move, 3 should start to step.
A second group could dance, if there is time.
Show Powerpoint Slide 6
See Apparatus List
See Safety Notes / The remainder of the class should watch and explain what they see.
The line should automatically form bunches which move along the line to represent the sound travelling. Point out that the children do not move along the line. Only the bunches move along: the individuals just vibrate.
Ask them how the dance could represent quiet sounds and loud sounds. / As the sound travels, the individual particles vibrate and do NOT travel with the sound.
This is called a sound wave.
6. Discussion
Show Powerpoint Slide 7
When the alarm rings we do not feel a rush of air. The sound wave travels from the alarm to our ears. / A sound wave travels from the source to our ears.
7. Demonstration
Singing rod
Hold the rod lightly with two or three fingers at its mid point and then with the other hand rub the rod slowly from the centre outwards in slow sweeping movements. The rod will vibrate and sound a note. The vibrations are longitudinal. If the end of the rod is pointed towards the class they will hear a louder sound.
See Apparatus List
Ask the class to hum gently and to feel their throats at the same time. / Invite the children to touch the end of the rod and feel the vibration. This is not felt along the rod only at the end showing the rod is vibrating longitudinally.
(A rod made of a different material or of a different length will produce a sound of a different frequency and can be used in later activities if available.)
Ask what they feel and explain that these are vibrations. They may have done this in at KS 1, but it is a quick way for them to learn what vibrations are. / Vibrating objects produce sound.
8. Quiet sounds
Ask them to be very quiet and try to make no sound at all. They quickly find that they need to be very still. Sounds outside the room such as traffic seem loud. / After a moment someone will move and make a chair squeak or drop something, which will sound loud. When they are very still, ask them to start to make very quiet sounds – they must not speak!
They find they need to move and perhaps tap something. / Reinforce that sounds are made when things move.
To make quiet sounds small movements are needed.
9. Loud sounds
If you think they will behave well you could make a pact that they will go quiet when you raise your hand. Then ask them to make loud sounds- without speaking. / They will find that loud sounds are associated with large movements.
During discussion link this with vibrations. / Loud sounds are made by large movements
10. Discussion about listening
Show Powerpoint Slide 8 / Ask them to describe the kitten’s ears.
They are large and point forward. The cat is able to detect very quiet sounds because the large ears collect sound waves over a wide area. The ears point forward so the kitten turns its head or its ears to hear where the sound comes from. / Some animals can hear very quiet sounds
11. Activity
The ends of the sound tubes should be placed over the ears of a volunteer. Then the tube tapped and the volunteer asked which side the sound comes from.
See Apparatus List / Human ears are on the sides of the head with small ear flaps that point slightly forward. The ears detect the sound and send messages to the brain.
The two ears send different signals so we know from which direction the sound is coming. / Human hearing is very sensitive to direction.
12. Extra
Show Powerpoint Slide 9
Absorption of sound
(note the kitten is much younger in this picture than in slide 9) / Ask why the kitten is looking unhappy?
They will suggest that it does not like the hat. Then ask if they think it will still be able to hear.
This can lead into a discussion about soft materials absorbing sound which would link well with investigation work that the teacher may be planning.
Point out that because the hat is thin it will not absorb all of the sound. / Soft materials absorb sound.
13. Discussion
Show Powerpoint Slide 10
The whales communicate with a sort of song. They make the sound underwater and it travels long distances through the water.
(Beluga whales are very social and make a wide variety of sounds.) / Ask them whether they can swim underwater. Ask whether they can hear if the side of the swimming bath is thumped when they are underwater.
They may point out that they do not hear voices above the water well. Explain this is because the sound does not pass through a change of material well. This will be useful when explaining ultrasound. / Sound will travel through water.
14. Activity Tunes from a coat hanger
See Apparatus List
Use a coat hanger with a piece of string tied at each corner as shown in the apparatus list.
Show the Marvin cartoon on Show Powerpoint Slide 11 after the volunteer has reported what was heard.
See Safety Notes / Ask for a volunteer. Wrap the ends of the string round a finger of each of the child’s hands. Then say ‘Now put your fingers in your ears’. Tap the coat hanger gently with a metal object. Ask whether the sound was loud. Tap again without the fingers in the volunteers ears. Discuss the difference in the loudness.
Explain that the sound travels through the metal and string more easily than through the air.
15. Extra - Bush Telephone Show Powerpoint Slide 12
See Apparatus List
Ask a child to take one cup as far as the string will allow across the classroom. Child 2, who should be close to the front of the class, should hold the second cup again an ear. Arrange that the string is held taut. Blindfold child 2 with a soft dark scarf. Then hold up a card showing a simple message. Ask child 1 to whisper the message into the cup and then ask child 2 what is heard.
This activity can be expanded by having a few cups linked together by taut string and then the message should reach children 2, 3 etc. / Child 2 should hear the message clearly
If a child takes hold of the string the listener will not be able to hear. Also if the string is slack nothing is heard.
Make sure that the children understand that the sound travels through the string. They might notice that the message can be heard very quietly close to the string – but not nearly as well as via one of the cups. / Sound will travel through string and other materials.
Sound does not only travel through air.
16. Extra Telephones
Show Powerpoint Slides 13,14
A very simple diagrammatic explanation of a telephone is provided. Explain that the sound is changed into an electrical signal by a microphone in a sound system – the information travels as an electrical signal through amplifiers etc to a loudspeaker. A loudspeaker or earpiece changes the electrical signal back into a sound message. A telephone works in a similar manner. / This has been included in response to questions from children during the trials.
The idea that the message can travel as an electrical signal can be linked back to human hearing. Point out that when sound reaches our ears then message is sent to our brain as an electrical signal.
17. Extra
Show Powerpoint Slide 15
Mobile phones
There is an extra stage in the communication with the sound changing to first an electrical signal then to a radio signal. / The children ask lots of questions and this is an opportunity to link the science with their everyday experiences.
18. Discussion
Show Powerpoint Slides 16,17,18
Link low notes and low pitch and also link high notes and high pitch.
(The children who play instruments may know the word pitch)
Ring a small bell when you show Show Powerpoint Slide 19 and ask whether the large bell would make the same sound.
See Apparatus List / Ask what noise a cow makes. They will enjoy making moooo sounds. Then ask what sound a baby mouse makes. They will squeak.
They will know that the cricket makes sounds by rubbing their legs (knees) together to produce an even high pitch sound.
Bring out – large objects make low notes and small objects make high notes.