P1.5.3 Sound Flashcards
What are sound waves?
Sound waves are longitudinal waves and cause vibrations in a medium, which are detected as sound.
Explain how humans hear.
- Sound waves are caused by vibrating objects. These mechanical vibrations are passed though surrounding medium as a series of compressions.
- Sometimes the sound will eventually travel through someone’s inner ear and reach their eardrum, at which point the person might hear it.
Why can’t sound travel in space?
Because it is a vacuum (there are no particles).
Sound travels faster in…
….solids than in liquids, and faster in liquids than in gases.
What are echoes?
Echoes are reflections of sound waves.
Why do you hear a delay between the original sound and the echoed sound?
You hear a delay between the original sound and the echoed sound because the echoes sound waves have to travel further, and so take longer to reach your ear.
Sound waves can refract if they enter different media. What happens as they enter denser material?
As they enter denser material they speed up.
Why does a big empty room sound completely different once you’ve out carpet, curtains and furniture in it?
When previously, sound waves were reflected by hard flat surfaces, the furniture now absorbs the sound quickly and stops it echoing around the room.
What determines the pitch of a sound?
The frequency.
A high frequency means a….
A low frequency means a….
…high pitch.
…low pitch.
What is the frequency?
The number of complete vibrations each second - so a wave that has a frequency of 100 Hz vibrates 100 times each second.
Transfer 1 kHz and 1 MHz to Hz.
1 kHz = 1000 Hz
1 MHz = 1000000 Hz
What affect does a high frequency have on the wavelength?
A high frequency means a shorter wavelength.
What determines the loudness of a sound?
The loudness of a sound depends on the amplitude of the sound wave.
The bigger the amplitude…
…the louder the sound.
