This week Think Lab has been playing host to a delegation of Chinese architects – hey, it’s all go here – so we set to work in our office instead. We already have a hundred snow globes strewn around the place, what harm is there in adding a little craft mess?
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Do you want to see the sound waves made by your voice? Make this simple tonoscope using a tube, plastic bag, some sugar or salt and a straw.
This page will print, but looks a little funky. Click the button for a PDF version which looks a bit better.
Make a hole in your tube about 1cm from the base with your sharp pencil. Put your sticky tack or rolled up tissue inside the bottom of your tube and then push your pencil in to make the hole.
Now cut a square of plastic from your bag or clingfilm. This needs fit over the top of your tube with about 2 cm of extra plastic all the way around.
Stick one side of the plastic to the side of your tube using sticky tape. Then stick the opposite side of the plastic to the of the tube, making sure the plastic covers the open end of the tube.
Now stick the bag to the tube at two more points. Then secure the plastic to the tube by wrapping tape all around. Make sure you don’t leave any gaps.
Put your straw into the hole at the bottom of your tube. Sprinkle a small amount of salt or sugar evenly over the plastic.
Put the tonoscope on a flat surface and make a noise with your voice into the tube. Watch what happens to the grains of sugar or salt on the plastic!
What happens to the grains when you make a loud noise?
What happens to the grains when you make a quiet noise?
What happens when you make a high pitched sound (like a squeal)?
What happens when you make a low pitched sound (like a growl)?
Whenever you speak or make a noise, your larynx (voice box) vibrates and moves the air around it in your throat and mouth. We call those air vibrations sound waves. Put your hand gently on your throat and make a noise with your voice. You should be able to feel your larynx vibrating in your throat. Sound waves travel through the air and into your ear, where they are sent as nerve signals to your brain so you can hear. To find out more about how this works, watch this BBC Operation Ouch video.
When you use your tonoscope, the vibrations of your voice travel along the straw into your tube. The sound wave then travels through the air inside the tube and hit the plastic covering the top of the tube, making it move.
The louder the noise, the bigger the vibration produced. When you make a loud noise, your grains will jump higher when they vibrate, and lower if you make a quieter sound.
The higher pitched the noise, the faster the vibration produced. If you make a high pitched noise, your grains will move faster, and a lower pitched noise will make them move slower.
What to do:
Blow up and tie your balloon. Hold the balloon close to your ear and tap lightly on the other side.
What is happening?
You should be able to hear a loud noise even though you are tapping lightly. This is because when you blow up the balloon you put more air molecules into the balloon. The air molecules in the balloon are closer together than ordinary air. This means the air in the balloon is a better conductor of sound waves than the ordinary air around you and so you heard a louder noise.
Collect 8 drinking straws. If they are the bendy type, cut off the bend and use the straight part of the straw. The first straw will need no cutting. Cut about 2 cm off the end of the next straw, 4 cm off the third straw, 6 cm off the fourth straw and so on until all 7 straws have been cut. Lay a piece of clear tape on the table, sticky side up, and arrange the straws on the tape from longest to shortest, with the tops of the straws all lined up with each other. Wrap more tape around the straws to secure them together. Blow over the top of the straws.
Which straw makes the highest pitch noise?
Which straw makes the lowest pitch noise?
Why do you think this is?
What is happening?
The pitch of a sound corresponds to the fast the sound wave is vibrating (the frequency): the higher the frequency, the higher the pitch. The shorter the straw, the higher the frequency of the sound wave and the higher the pitch. The longer the straw, the longer the frequency of the sound wave and the lower the pitch. To find out more about pitch, click here and watch this video.
20 minutes or so.
Age 3 and up.
You know your children better than anyone, and you should judge whether they’re ready for this activity. You might want to think in particular about:
Careers Link: Audiologist
If you enjoyed investigating sound, you may like to be an audiologist when you are older.
Audiologists are healthcare professionals who are specialists in human hearing. They work with patients from newborn babies to the elderly and help people who have hearing, balance or other ear related problems. They may be involved in screening for hearing loss or fitting hearing aids.
Audiologists are observant, communicative and patient.
Clinical audiologist Lynzee tells us more about what she does in the interview below.
A sound engineer works specifically with the mechanical and technical aspects of recording, mixing, reproducing and manipulating the electronic effects of sound. They control microphones, sound levels and outputs along with their experience of acoustics to produce the best quality of sound suitable for purpose. Sound engineers don’t always work in music. There are specialist areas of sound engineering to become involved in, such as studio engineering, live sound engineering, game and audio design or audio post engineering which involves mixing and editing sound for television and movies.
Attributes: tenacious, self-motivated, organised
How does my Loud Lolly work?
Today you made a harmonica using lolly sticks, plastic straws and elastic bands. You may have noticed that you can use it to make a pretty loud noise!
Sound is the energy produced by vibration which travels through the air and into your ear. This causes your eardrum start to vibrate and your brain to interpret that vibration as sound.
When you blow into your Loud Lolly, the straws and rubber bands start to vibrate from the force of your breath which causes the sound you hear.
Experiment with your Loud Lolly
If you move the two straws closer together or farther apart, how does the sound change? What happens when you pinch the Loud Lolly together more with your fingers or your lips?
What to do:
Blow up and tie your balloon. Hold the balloon close to your ear and tap lightly on the other side.
What is happening?
You should be able to hear a loud noise even though you are tapping lightly. This is because when you blew up the balloon you forced the air molecules inside the balloon closer to each other. This means they become a better conductor of sound waves than the ordinary air around you and you hear a louder noise.
What to do:
Cut a piece of string about 5 times your height. Thread the tin cans onto the piece of string. Make sure that the cans are bottom to bottom. Tie large knots in both ends of the string. Pull the string tight to use. Now try to use the tin can telephone with a slack string – does it work? Why do you think this is? Tighten the string again and try touching it gently whilst you speak into the can. What can you feel? Why do you think this is? What happens if you attach a third can on a piece of string?
Safe science: tin cans may have sharp edges so examine the cans carefully before use.
What is happening?
Sound is made up of vibrations. When you speak you vibrate the air coming out of your mouth. This travels across the room and is picked up by the ears of anyone close enough to hear. The tin can collects those vibrations and passes them along the string – that’s why you can feel the string vibrating. What happens to the vibrations if you shout or whisper? Here’s a challenge – can you find a way of using the tin can telephone around a corner?
What to do:
Collect 5 or more of the same sized drinking glasses, some water and a wooden stick such as a pencil. Line up the glasses next to each other and fill them with different amounts of water. The first glass should have just a little bit of water in the bottom, then each glass needs a little more until the last one, which should be almost full.
Hit the glass with the least amount of water and listen to the sound, then hit the glass with the most water.
Safe science: make sure you have an adult to supervise this investigation as glass may smash if used incorrectly.
Which makes the higher sound?
Hit the other glasses and listen to noise they make.
Can you make a tune?
What is happening?
The glass with the most water will have the lowest tone when hit with the pencil while the glass with the least water will have the highest. When you hit the glass you make small vibrations, creating sound waves which travel through the water. More water creates slower vibrations and a deeper tone, while less water creates faster vibrations and a higher tone.
What to do:
Collect 8 plastic drinking straws. If they are the bendy type, cut off the bend and use the straight part of the straw. The first straw will need no cutting. Cut about 2 cm off the end of the next straw, 4 cm off the third straw, 6 cm off the fourth straw and so on until all 7 straws have been cut. Lay a piece of clear tape on the table, sticky side up, and arrange the straws on the tape from longest to shortest, with the tops of the straws all lined up with each other. Wrap more tape around the straws to secure them together. Blow over the top of the straws.
Which straw makes the highest pitch noise? Which straw makes the lowest pitch noise? Why do you think this is?
What is happening?
The pitch of a sound corresponds to the frequency of the sound wave: the higher the frequency, the higher the pitch. The shorter the straw, the higher the frequency of the sound wave and the higher the pitch. The longer the straw, the longer the frequency of the sound wave and the lower the pitch. To find out more about pitch, click here and watch this video.
Can you change the volume and pitch of sound in a variety of ways? This box has the equipment you will need to create, measure and change sounds scientifically in your classroom.
Year 4 could use this box to find patterns in the sounds that are made by tuning forks, and different lengths of boomwhacker tubes, to investigate pitch. They may use different materials in the sound boxes to investigate which provides the best insulation against sound. The sound level monitor could be used to investigate volume, and the slinkies to create a scientific model of how sound travels through different materials to your ear.
Year 4 Science: Sound
Download full contents list here.
Congratulations, you made it to the Science for Families Sound page!
Let’s test your hearing. Well… not exactly test. A proper hearing test would need very carefully controlled conditions, whereas you’ve got the speakers on your laptop or mobile phone or whatever. But there is a neat little comparison we can make. You’ll need:
Below, we have several different sounds. They’re simple tones at different frequencies, which means some are higher-pitched than others. Start by playing this first tone:
This tone is a frequency of 1000 Hz. That means it’s vibrating your speakers 1000 times every second. You and your adult will very likely both be able to hear this. If you can’t, it’s most likely that your computer isn’t making any sounds. Try talking to each other to check that you haven’t turned your ears off, then see if you can fix your computer speakers.
Now try the following tones one at a time, and see if you can both hear them all. They start much higher-pitched than the first tone, and go up from there. Be warned that none of them sound very pleasant!
Turn your speakers down! These sounds are very high-pitched, and could sound a bit painful.
It’s quite likely that, at some point, one or both of you stopped being able to hear the sounds. This could be simply because your computer speakers can’t play really high-pitched sounds, or that they sort-of can but they’re very quiet.
But it’s also the case that your adult’s ears have been around longer than yours have. They’re likely are a little bit worn out, and therefore aren’t as good at picking up very high frequency noises. Your ears are younger and probbaly still able to pick up those super high frequencies. If you want to experiment a bit further, try the tones on someone even older.
…that doesn’t mean you have a hearing problem. Yes, the text above says that it’s probably your computer that’s messing up rather than your ears, but we figured you might actually read colourful and reassuring text like this.
We hear sounds because of vibrations. If your alarm clock goes off in the morning, you hear it because the alarm vibrates the air, those vibrations reach your ear, then tiny hairs in your ear pick up the vibrations. Here’s a video with a lovely explanation of sound:
This morning Think Physics hosted year 7 students from Kenton School and year 6 students from a number of primary schools.
During the morning, we thought about what j0bs can be done if you study science by looking at photos of different people. There were some very surprising people, including a snowboarding mechanical engineer. You can see the pictures here.
We also tried to work out what were in some ‘mystery boxes’. There was a lot of shaking and listening going on. This activity reminds us that science doesn’t know all the answers. We talked about how science is all about:
Next came sound. The year 7 pupils explained to their year 6 partners how sound travels through the air, and they modeled what a sound wave looks like.
We heard how sound travels differently through the air and through solids using a coathanger and a slinky spring. Do ask for a demonstration!
Finally we made loud lollies and sorry if that’s already drive you up the wall. We used them to discuss how you would plan an investigation, and how to control all the factors that might affect our results.
