You probably already know that sound is a vibration . If you could see sound , the vibrations would look like waves . The note that you hear is set by the frequency of the vibration . This is the number
Amplitude QUIETER
LOWER PITCH
LOUDER
HIGHER PITCH of complete waves ( from peak to peak ) in a second . The peaks are close together in the sound waves at the bottom right of the picture ; this means they have a high frequency and will make a high note . The waves on the bottom left of the picture here have a lower frequency because the peaks are more spread out ; these notes will be low . You can test this if you put your hand on your throat and hum a low note . Can you feel it ? Now make a high note . The vibrations have changed from low frequency to high frequency . Did you feel the difference ?
Some artists and musicians use sound vibrations to make amazing artworks . This area of art is called cymatics . The most famous way of doing this is to use a Chladni plate , invented by Ernst Chladni in around 1787 . It is a thin metal plate mounted on a post so that the edges of it can vibrate freely . To make it work , you sprinkle a thin layer of sand or salt onto the plate then make it vibrate by moving a violin bow on the edge of the plate . When the plate vibrates , a pattern is made as the sand is moved to the areas of the plate that are not moving . If you change the note , or hold the edge of the plate , the metal vibrates at a different frequency and the pattern changes .
Grace Digney is an artist from Newry in Northern Ireland ( www . gracedigney . com ). She captures the shapes of vibrations using an eidophone ( see the opposite page for how to make your own version ).
This picture shows the shapes of different laughter , made in bronze so you can feel the shapes . She has recently investigated some bodily sounds and says ‘ I know what a heartbeat , sneeze , burp and passing gas looks like ! They look great on my wall !’
Take a look at this fascinating video , which shows musician Nigel Stanford using a range of cymatic techniques : https :// tinyurl . com / o6d875r
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