10.1 sound the horns because the swine is here Flashcards
(30 cards)
what is soudn
Form of energy caused by vibration
Sound require a?
Medium to propogate
Sound can propagate through ___ but cannot through ___
Liquid, solid, gas
Vacuum
State how sound is transferred from a bell
Metal surface of bell vibrate -> air molecules near surface also vibrate & collide with air molecules nearby -> transferred in form of wave
How is transfer of sound in solid
Very rapid
Particles at one end start to vibrate -> causes nearby particles to also vibrate -> solid particles arranged very closely
How is speed of sound in liquid
Loose arrangement of particles -> less rapidly
How is speed of sound in gas
Very slowly -> arrangement of gas particles - far apart from each other -> delay in transfer of vibration
If sound transfers very rapidly in solids, why cant we hear in solid
It takes more energy to vibrate a solid than a gas
Which types of surface can reflect and absorb sound better & worse
Hard and smooth - reflector
Soft and rough - absorber
Characteristics of R & A of sound is same as?
Characteristics of light
What are two main properties of sound
Frequency -> pitch -> hertz (Hz)
Amplitude -> strength / loudness
What is a hertz
Number of oscillations per second
state relationship between change in amplitude & effect
Amplitude increase -> louder sound
state relationship between change in frequency & effect
Frequency increase -> higher pitch
What is the Doppler effect
Apparent change in frequency caused by the relative movement of sound source, rm of observer / both
Explain the Doppler effect of an ambulance
Frequency heard increases when approaches the stationery observer
Frequency heard decreases when drives away
On a piano, a lower note means lower?
Frequency / pitch
If a spoon is knocked on differently filed glass, state the pitches and why
Tapping spoon on glass -> vibration -> sends sound wave through water
Most water -> slower vibration -> lower sound
If you blow on differently filed glass, state the pitches and why
Blow across the top of the bottle -> set the air molecules vibrating -> produce sound waves
Least filled -> lowest sound -> more air -> slower vibrationi
What is an echo
Produced when sound waves are reflected from hard surface to the listener
What are characteristics of echo
Sounds the same as original sound
Takes some time to reach listener’s ears
What is condition for echo
At least 17 m from object
Time must be 0.1 sec (or else will merge with original)
What is application of reflection of sound wave in human life
Ultrasound, sonar
What is ultrasound & characteristics
Sound wave with frequency > 20000 Hz
Cannot be heard by humans - can be heard by animals (bats) -> navigation
