Intermediate 1 Physics

Intermediate 1 Physics Sound and Music • Sound Waves • Speed of Sound • Using Sound • Amplified Sound Beath High School - Int 1 Physics

Intermediate 1 Physics Sound and Music Sound Waves Beath High School - Int 1 Physics

Sound Waves Vibrations Musical instruments produce sound when part of the instrument v _ _ _ _ _ _ _ A guitar string vibrates when it is plucked. vibrates. Beath High School - Int 1 Physics

Vibrations air A trumpet blasts out sound when the a _ _ inside it vibrates Energy is transferred from the vibrating object to the listener by sound w _ _ _ _ which travel through the air. These sound waves make the air v _ _ _ _ _ _ . waves vibrate. Beath High School - Int 1 Physics

Frequency Each note or sound has a frequency which is measured in h _ _ _ _ (Hz). A tuning f _ _ _ has the frequency engraved on it. This vibrating fork will produce 256 vibrations every s _ _ _ _ _ . This means that 256 sound w _ _ _ _ are produced in one second. hertz fork second. waves Beath High School - Int 1 Physics

Frequency F _ _ _ _ _ _ _ _ = number of waves produced in one second. Frequency Beath High School - Int 1 Physics

Frequency higher A whistle produces a h _ _ _ _ _ frequency sound than a vibrating drum. The whistle has a much higher p _ _ _ _ . pitch The higher the pitch means the higher the f _ _ _ _ _ _ _ _ frequency Beath High School - Int 1 Physics

Detecting Sound Sound S _ _ _ _ can be taken in by a microphone and a trace displayed on an oscilloscope. Beath High School - Int 1 Physics

Loud and quiet A loud sound transfers more e _ _ _ _ _ so the oscilloscope trace will have a l _ _ _ _ amplitude. The amplitude of a wave is the distance from the m _ _ _ _ _ of the wave to the top or bottom of the wave. energy large middle Beath High School - Int 1 Physics

Loud and quiet Beath High School - Int 1 Physics

Loud and quiet less A soft/quiet sound transfers l _ _ _ energy so the oscilloscope trace will have a s _ _ _ _ amplitude small Beath High School - Int 1 Physics

High and Low Frequency The effect of changing the frequency of a note can be seen on the oscilloscope screen. Sound _ has a higher frequency than sound _ . B A Beath High School - Int 1 Physics

High and Low Frequency octave If the frequency is doubled, we say that sound B is an o _ _ _ _ _ higher than sound A. frequency: 256 512 1024 (Hz) one octave t _ _ octaves two Beath High School - Int 1 Physics

Changing the Note A musician tunes a guitar by making the string t _ _ _ _ _ _ or looser. While playing the guitar, the note is changed by altering the l _ _ _ _ _ of string which vibrates. tighter length Beath High School - Int 1 Physics

Changing the Note • S _ _ _ _ strings produce a higher frequency than long strings. • T _ _ _ _ strings produce a higher frequency than slack strings. Short Tight Beath High School - Int 1 Physics

Changing the Note length An organ produces a variety of musical notes which depend on the l _ _ _ _ _ of the air column which vibrates. The shorter pipes have the shorter air columns which produce the h _ _ _ _ _ frequency notes. higher Beath High School - Int 1 Physics

Intermediate 1 Physics Sound and Music Speed of Sound Beath High School - Int 1 Physics

Speed of Sound During a thunderstorm, the lightning flash is seen a short time b _ _ _ _ _ the roll of thunder is heard. This is due to the fact that l _ _ _ _ travels much faster than sound through the air. between light In air: Speed of light = 300 000 000 m/s Speed of sound = 340 m/s Beath High School - Int 1 Physics

Calculating the Speed of Sound In a laboratory the speed of sound can be calculated using the formula below. (meaning; speed equals distance d _ _ _ _ _ _ by time) divided Beath High School - Int 1 Physics

Speed of Sound : Apparatus different Beath High School - Int 1 Physics

Speed of Sound starts A loud sound is made. As the sound reaches microphone A, the timer s _ _ _ _ _ . When the sound waves reach microphone B, the timer s _ _ _ _ . The distance between the microphones is measured with a m _ _ _ _ stick. The experiment can be r _ _ _ _ _ _ _ to calculate a more accurate, average result. stops metre repeated Beath High School - Int 1 Physics

Speed of Sound Example: Recorded times: 0.0030 s, 0.0029 s, 0.0031 s, 0.0027 s, 0.0029 s Average time = 0.0146/5 = s 0.0029 Distance travelled = 1 metre Speed = distance/time = 1.0/0.0029 = m/s 344.8 Beath High School - Int 1 Physics

Intermediate 1 Physics Sound and Music Using Sound Beath High School - Int 1 Physics

Using Sound solids, gases. Sound can travel through s _ _ _ _ _ , liquids and g _ _ _ _ . The only thing that sound cannot pass through is a v _ _ _ _ _ . vacuum. A vacuum is an e _ _ _ _ space, so there are no particles to pass on the vibrations. empty Beath High School - Int 1 Physics

Using Sound sounds When listening to music, you hear s _ _ _ _ _ with a wide range of frequencies. We can detect sounds that range from about 20 hertz to 20 000 hertz. As we get o _ _ _ _ , the upper limit gradually falls to about 15 000 hertz. older Some animals can detect higher frequency sounds than h _ _ _ _ _ . humans. Beath High School - Int 1 Physics

Using Sound - Ultrasound upper Sound beyond the u _ _ _ _ limit of human hearing (20 000 Hz) is called ultrasound. Ultrasound can be used in hospitals to scan the b _ _ _ in the mother's womb. This can be used by a computer to produce an i _ _ _ _ of the baby on a screen. baby image Beath High School - Int 1 Physics

Using Sound - Ultrasound sonar A system called s _ _ _ _ is used by fisherman at sea. The ultrasound signal is transmitted towards the sea bed and an e _ _ _ is detected. Shoals of f _ _ _ are located by this method. echo fish Beath High School - Int 1 Physics

Sound Levels loud The sound level of a noise means how l_ _ _ it is. The sound level varies depending on the source of the sound. Sound level is measured in d _ _ _ _ _ _ _ (dB). decibels Beath High School - Int 1 Physics

Sound Levels Jet 130 J _ _ engine at 50 metres 100 Pneumatic d _ _ _ _ 70 Rush hour t _ _ _ _ _ _ 0 S _ _ _ _ _ _ drill Sound l _ _ _ _ (dB) traffic level Silence Beath High School - Int 1 Physics

Sound Levels noise When sound levels rise to unacceptable levels, the problem is described as n _ _ _ _ pollution. There are many sources of noise pollution, such as aircraft noise or pneumatic drills. Exposure to high sound levels over a long time can d _ _ _ _ _ our hearing. Listening through stereo headphones will produce a harmful effect if the v _ _ _ _ _ is turned to maximum. damage volume Beath High School - Int 1 Physics

Intermediate 1 Physics Sound and Music Amplified Sound Beath High School - Int 1 Physics

Amplified Sound listen A stereo system can be used to l _ _ _ _ _ to a compact disc (CD) or a radio programme. No matter what function is selected, the signal passes through an amplifier which turns a small amplitude electrical s _ _ _ _ _ into a higher amplitude one. signal Beath High School - Int 1 Physics

Amplified Sound Only the amplitude of the signal is changed. The frequency does n _ _ change. not When announcements are made at airports and stations, the message has to be changed from sound into e _ _ _ _ _ _ _ _ _ signals and back to sound. electrical Beath High School - Int 1 Physics

Amplified Sound When announcements are made at airports and stations, the message has to be changed from sound into e _ _ _ _ _ _ _ _ _ signals and back to sound. An electronic system of 3 parts is used to amplify the s _ _ _ _ given out by the announcer electrical signal Beath High School - Int 1 Physics

Amplified Sound microphone electrical amplifier stronger loudspeaker sound Beath High School - Int 1 Physics

Voltage Gain The performances of different amplifiers can be compared by finding the gain of the amplifier. Beath High School - Int 1 Physics

Voltage Gain Example: Find the voltage gain of the following amplifier. Beath High School - Int 1 Physics

Voltage Gain = 400 N.B. Voltage gain is just a number. It has no u _ _ _ . unit Beath High School - Int 1 Physics

Playback voice A recording of your own v _ _ _ _ will sound a bit strange when it is played back from a cassette. This is because we normally hear our own voice by: vibrations of bones in our s _ _ _ _ and vibrations in the air being detected by our e _ _ _ When we listen to a recording of our own voice we hear it by: vibrations in the a _ _ being detected by our ears only. skull ears air Beath High School - Int 1 Physics

Playback high A CD (compact disc) is a source of h _ _ _ quality sound. As the CD spins inside the CD player, light from a l _ _ _ _ reflects off the CD. There is no wear and tear of the disc surface and there is very little background n _ _ _ _ . laser noise. Beath High School - Int 1 Physics

Intermediate 1 Physics Sound and Music End of Unit Beath High School - Int 1 Physics

Intermediate 1 Physics