7L - Sound Flashcards
Does sound transfer energy?
Yes
When is sound made?
When things vibrate
Why does sound need a medium (substance) to pass on the vibrations?
The vibrations are passed on by particles.
Can sound travel through a vacuum?
No. (no particles, so vibrations can’t be passed on).
What is the speed of sound in air?
340 m/s
Where does sound travel fastest: in solids, liquids or gases?
Solids, then liquids then gases.
Why does sound travel faster in solids than in gases?
Particles are closer together so they hit each other with more easily and so the energy is more likely to be passed on.
What is the frequency of a wave?
The number of complete waves passing a point each second.
What is the unit for frequency?
Hertz (Hz) (1 hertz is 1 wave per second)
What is pitch?
How high or low a sound is.
What pitch would a wave with high frequency have?
High pitch.
What wave would a wave with low frequency have?
Low pitch.
What is the amplitude of a wave?
How far particles move as the vibrations pass.
Name two synonyms of ‘loudness’ of a sound.
Volume. Intensity.
The higher the amplitude, the higher the…
Volume/intensity/loudness of the sound.
What is used to measure the loudness of a sound?
A sound intensity meter.
What are the units for the intensity of a sound?
Decibels (dB).
Can sound waves be reflected?
Yes. Usually if the material is hard.
Can sound waves be absorbed?
Yes. Usually with soft materials.
The sound waves that aren’t reflected or absorbed by the material are…
transmitted by the material.
Why does the intensity of a sound gets lower as you get further from its source?
The energy being transferred spreads out in all directions because the particles move in all directions.
How is sound recorded by a microphone?
Sound waves make a diaphragm vibrate. The vibrations are then converted to electrical signals.
How can ears detect sound and send it to our brains?
- Sound waves make the eardrum vibrate. 2. Vibrations are amplified by 3 small ear bones. 3. Vibrations pass to the liquid inside the cochlea. 4. Tiny hairs inside the cochlea detect them and send impulses along the auditory nerve to our brain
What is an auditory range?
The range of frequencies an animal can hear.
What is the auditory range for humans?
20 - 20000 Hz
What is infrasound?
Sound with frequencies below 20 Hz
What is ultrasound?
Sound with frequencies above 20 000 Hz
What are the uses of sound? (5)
- Communication. - Ultrasound for echolocation (dolphins and bats). - Ultrasound in sonars (finding depth of sea or locating fish or submarines). - Ultrasound to clean delicate objects (jewellery) - Ultrasound in physiotherapy to relieve pain and aid healing.
In transverse waves, particles vibrate…
at right angles to the direction of travel.
In longitudinal waves, particles vibrate…
In the direction of travel.
Name a transverse wave
Water waves.
Name a longitudinal wave
Sound waves.
What do all waves have in common? (3)
- Transfer energy without transferring matter. - Can be reflected, transmitted or absorbed. - Can affect other waves by superposition.
What happens during superposition?
The effects of the waves add up or cancel out.
How do sonars measure the depth of the water?
- Send ultrasound waves. - Sound waves then reflect and travel back to the sonar. - The sonar detects the waves and measures the time taken: the greater the time taken, the more deep the water is.
What is A?
Ear canal
What is B?
Ear drum
What is C?
Ear bones
What is D?
Auditory nerve
What is E?
cochlea
How are the air particles at A?
Closer together
How are the air particles at B?
Further apart.
What is A?
Crest
What is B?
Through
What is C?
Amplitude
What is to vibrate?
To move forwards and backwards.
What are the vocal folds?
Flaps of skin in our throat that vibrate to make the sound when we speak.
What is a medium?
Any subtance through which something happens.
What is a pressure wave?
Waves where the vibration of particles transfers energy.
What is a source?
Where waves begin.
What is a vacuum?
A completely empty space, that contains no particles.
What is density?
A measure of a substance’s mass per unit volume (g/cm^3).
What is a line (or curve) of best fit?
A lne drawn through a set of points on a scatter graph so that about half of the points are on each side of the line.
What is quantitative data?
Data that can be measured with numbers.
What is qualitative data?
Data that can be described with words, rather than measured with numbers.
What is an oscilloscope?
An instrument which shows a picture of a wave on a screen.
What is the trace on an oscilloscope?
The line on an oscilloscope screen that represents a wave.
What is the auditory nerve?
The nerve that carries impulse from an ear to the brain.
What is the diaphragm of a microphone?
A thin sheet of flexible material.
What is ear protection?
Ear plugs or covers for the ears that stop loud sounds damaging the ear.
What is an impulse?
An electrical sign that travels in the nervous system.
What is echo?
Sound that we hear again after it has reflected off a surface.
