P1.2 Sound Flashcards
What do waves transfer?
Energy
What causes waves?
Oscillations or vibrations
What does frequency mean?
The number of waves per second
What is the unit for frequency?
Hz (Hertz)
What is a wavelength?
The distance from one point on a wave to the same point on the next wave?
What is the top of the wave called?
Peak or Crest
What is the bottom of the wave called?
Trough
What is the amplitude of the wave?
The distance from the middle to the top of the wave
What are the two types of wave?
Transverse and Longitudinal
What is a transverse wave?
A wave where the oscillations are 90 degrees to the direction of the wave
What is a longitudinal wave?
A wave where the oscillations are parallel to the direction of the wave
Is sound a longitudinal or transverse wave?
Longitudinal
What is a compression?
A part of the longitudinal wave where springs are close together
What is a rarefaction?
A part of the longitudinal wave where springs are far apart
What is meant by reflection
Where waves ‘bounce’ off a surface.
What is the technical term for when waves add together?
Superpose
What do longitudinal waves require to travel?
A material or medium to travel though
Can sound travel through a vacuum?
No
What is the speed of sound in air?
340 m/s
What is the speed of light?
300,000,000 m/s
Can light travel through a vacuum?
Yes
How can we ‘see’ sound waves?
Use an oscilliscope
What happens when you increase the frequency of a sound wave?
It will be higher pitch
What happens when you increase the amplitude of a sound wave?
It will be louder
What range of frequencies can humans hear?
20 - 20,000 Hz
How do we measure the loudness of a sound?
Using the decibel (dB) scale
If a sound is 40 dB and then increasing loudness to 50 dB - how many times louder is the new sound?
10 times louder!
What can you use to prevent damaging your ear drum?
Ear defenders
What is an echo?
A reflected sound wave
A sound wave is emitted, travels to a building, reflects and is then detected 5 seconds later. How far away is the building?
Total distance = speed x time = 340 m/s x 5 s = 1700 m. 1700 m is the distance to travel to the building AND back. So the building is 850 m away.
What can ultrasound be used for?
Prenatal scans, echolocation
