8 L Sound and hearing Making sounds Hearing

8 L Sound and hearing Making sounds Hearing and deafness Too loud! © OUP: To be used solely in purchaser’s school or college

8 L Sound and hearing Making sounds © OUP: To be used solely in purchaser’s school or college

8 L Sound words Match the words to the definitions. 1 vibration 2 pitch 3 loudness 4 sound 5 amplify A how E a backwards high or low andit forwards sounds tomovement the listener which transmits sound B how A vibrations high or that lowcan it sounds be heard to the listener C to D how make loudsound or quiet louder it sounds to the listener D vibrations B how loud or that quiet canitbe sounds heardto the listener E to C a backwards make sound and louder forwards movement which transmits sound © OUP: To be used solely in purchaser’s school or college

8 L Describing waves What does a large amplitude tell you about the sound? What does a large number of waves (frequency) tell you about the sound? What unit is used to measure frequency? © OUP: To be used solely in purchaser’s school or college

8 L Sound pictures Match the description to the oscilloscope pattern: A B C D 1. Low-pitched sound, very loud D 2. Loud, high-pitched sound C 3. Medium sound with medium pitch B 4. Quiet, high-pitched sound A © OUP: To be used solely in purchaser’s school or college

8 L Sound speeds Concorde was the first passenger jet to travel faster than the speed of sound. But how fast is that? The speed of sound: In air = 330 metres per second In water = 1500 metres per second In steel = 6000 metres per second Why did native American trackers put their ear to the ground if they wanted to listen for their prey? © OUP: To be used solely in purchaser’s school or college

8 L Rock legends? 1. I can increase the pitch of a note on a guitar by. . . a) plucking the string harder b) tightening the string c) holding the guitar tighter. 2. I play the lowest notes on an electric guitar by. . . a) not pressing on the strings on the fretboard b) touching the strings very gently c) turning the volume down on the amplifier. © OUP: To be used solely in purchaser’s school or college

8 L Rock legends? 3. Hitting the strings hard on a guitar will. . . a) make the note louder b) make the note higher pitched c) hurt my fingers. 4. The sound from an electric guitar dies away when. . . a) the string stops moving b) the guitarist stops plucking the strings c) the strings are magnetised. © OUP: To be used solely in purchaser’s school or college

8 L Rock legends? 5. A drummer can change the pitch of the drum by. . . a) changing the tightness of the drum skin b) hitting the skin harder c) using different drumsticks. 6. A drummer grabs hold of a vibrating cymbal to. . . a) stop it making a sound b) change the pitch of the sound c) stop it falling off the stage. © OUP: To be used solely in purchaser’s school or college

8 L What is sound? Sound is created by something vibrating. Imagine the surface of a drum. As the skin wobbles it pushes on the air next to it and squeezes it to make a little area of high pressure. © OUP: To be used solely in purchaser’s school or college

8 L What is sound? Then the skin moves the other way and creates an area of low pressure. If this happens over and over again you get areas of high and low pressure being made. These areas pass through the air and to our ears where we detect them as sound. © OUP: To be used solely in purchaser’s school or college

8 L Match signals to patterns of particles We can see these areas of high pressure with a microphone and an oscilloscope. © OUP: To be used solely in purchaser’s school or college

8 L The frequency range Make a list of these in order of frequency, starting with the lowest. A The D Rumble notefrom middle an earthquake C in the middle of a piano keyboard B Bottom string on a bass guitar A The note middle C in the middle of a piano C keyboard Typical whistle for a dog D The Rumble fromnote an earthquake E highest sung by a human being E Typical The highest note by a human being C whistle forsung a dog © OUP: To be used solely in purchaser’s school or college

8 L I’ll name that tune in. . . Match the oscilloscope traces to the source of the sound. A B C D 1. A flute playing a single clear note B 2. A dog whistle C 3. A milk bottle dropped onto a floor D 4. A rumble of thunder A © OUP: To be used solely in purchaser’s school or college

8 L Sound as a … sound? True or false? 1. The softer you hit a drum, the quieter the sound. TRUE 2. Louder sounds are higher pitched. FALSE 3. Bigger vibrations make louder sounds. TRUE 4. Hollow objects make sounds louder. TRUE 5. Carpets and curtains make sounds louder. FALSE © OUP: To be used solely in purchaser’s school or college

8 L Sound as a … sound? True or false? 1. High sounds have a low frequency. FALSE 2. Dogs can hear higher pitched sounds than humans can. TRUE 3. Some sounds can make you deaf. TRUE 4. Hard surfaces reflect sound. TRUE 5. Sound travels faster in water than steel. FALSE © OUP: To be used solely in purchaser’s school or college

8 l Sound and hearing Hearing and deafness © OUP: To be used solely in purchaser’s school or college

8 L The human ear © OUP: To be used solely in purchaser’s school or college

8 L Hear this! ear flap (pinna) bones of middle ear sound waves Which parts can move? Which part carries a nerve signal? Which part is made of bone? © OUP: To be used solely in purchaser’s school or college nerves to brain eardrum cochlea

8 L Batty! Insect-eating bats use sounds with a frequency of 80 000 Hz (or 80 k. Hz) to ‘see’ their prey. The bat sends out a sound and then listens for the echo as it bounces back from the insect. The bat compares the sound it hears from both ears to work out the direction the insect is in. What would happen to a bat if it went deaf in one ear? © OUP: To be used solely in purchaser’s school or college

8 L Sound and hearing Too loud! © OUP: To be used solely in purchaser’s school or college

8 L Measuring loudness I’ve asked you to turn that rubbish down! It’s not as loud as you have the television. I’ve already turned it down – and it’s not rubbish! It’s too loud. You’ll damage your ears. Why do we need a way to measure the loudness of sound? What unit is used to measure sound? © OUP: To be used solely in purchaser’s school or college

8 L Hear this! © OUP: To be used solely in purchaser’s school or college