Topic 3.4 Sound Flashcards
What are sound waves?
- Sound waves are longitudinal waves.
- Sound is produced by the vibration of particles in a medium (the substance that waves travel through).
- The vibrations mean that sound waves travel in a series of compressions (where the medium is squashed together) and rarefactions (where the medium is stretched apart).
How does sound travel through solids?
Sound waves cause vibrations through the solid.
What type of waves are sound waves?
Longitudinal waves.
Can sound travel through a vacuum?
No, sound requires a medium to be transmitted.
What is an echo?
A reflected sound wave
What is the speed of sound in air?
343 m/s
What is the speed of sound in steel?
5130 m/s
How does the speed of sound compare in solids, liquids and gases?
It is fastest in solids and slowest in gases.
What is the range of frequencies audible to the human ear?
20 Hz - 20kHz
(20-20000Hz)
What is ultrasound?
Sound with a frequency higher than 20kHz.
Describe the features of a longitudinal wave.
Longitudinal waves have compressions and rarefactions.
What wave property affects the volume of sound?
The amplitude (greater amplitude = louder sound).
What wave property affects the pitch of sound?
The frequency (higher frequency = higher pitch).
Describe applications of ultrasound
Ultrasound is used largely in medical imaging, specifically pregnancy scanning, as it is non-ionising so it does not increase the risk of cancer.
How would you do an experiment to determine the speed of sound in air?
You would need:
- Source of sound (starter pistol)
- Measuring tape
- Stopwatch
Readings you would take:
- Distance and time between flash and bang
How would you calculate the speed:
- You would calculate the speed by using distance/time
How to make it more accurate:
- Repeats
Draw a diagram showing compressions and rarefactions and label the wavelength
