Sound Flashcards
How does sound travel through solids?
Sound waves cause vibration through the solid
What type of wave 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
How can the speed of sound be
measured?
Make a noise at a known distance from a solid wall. Record the time for the echo to be heard. Then half the time and use speed = distance/time to calculate speed.
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- 20000 Hz
What is ultrasound?
Sound with a frequency above 20000 Hz
Describe the features of a longitudinal
wave.
Longitudinal waves have rarefractions amd compressions
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).
How can ultrasound be used to measure
distances?
-When waves reach a boundary between two media, they are partially reflected
-The speed of the waves is constant
-The time between emission and detection can be used to calculate the distance
(remember to halve the time; the recorded time is for the distance there and back)
Describe applications of ultrasound
Ultrasound is largely used in medical imaging ( pregnancy) as it is not ionizing so it does not increase the risk of cancer
