waves Flashcards
what are waves? (2 marks)
-waves transfer energy without transferring matter
-particles oscillate around a fixed point
two types of waves?
Longitudinal
Transverse
Longitudinal: describe the vibrations
the vibrations are parallel to direction of travel
Longitudinal: Two parts of longitudinal waves and where are they?
Compression- closer waves
Rarefraction- Further away waves
Transverse waves: describe the vibrations
The vibrations of transverse waves are at 90-degree angle to the direction of travel
Transverse: Two parts of transverse waves?
Peaks and troughs
peaks- the highest point above rest position
troughs-lowest point below rest position
Differences between longitudinal and transverse waves: (2 points each)
Longitudinal:
-vibrations are parallel to direction of travel
-they have compressions and refractions
Transverse:
-vibrations are at a 90-degree angle
-they have peaks and troughs
Keywords:
Amplitude
-Distance from the equilibrium to the peak or trough of a wave
Wavefront
- a wavefront is used to represent a single wave
Frequency
-the number of waves passing a point in a second (Hz)
Wavelength
-Distance between two peaks on one wave
Time period
-Time taken for a wave to pass a point
wavespeed equation
waves speed (m/s) =frequency (hz) x wavelength (m)
frequency equation
frequency=1/time period (s)
types of longitudinal waves:
Sound waves
P waves
types of transverse waves:
Electromagnetic waves (which can move in a vacuum)
Ripples on the surface of water
s waves
what is the doppler effect:
-the apparent change
-in wavelength and frequency of a wave
-emitted by a moving source
Describe the doppler effect in terms of frequency:
the pitch goes from high to low frequency as a vehicle passes by
what happens to waves when an object is moving?
waves get squashed together at one end of the object and stretched on the other end
when an object is moving (in terms of wave speed, frequency and wavelength..
wave speed is constant
frequency increases
wavelength decreases
waves can be…
(hint: two r’s)
reflected and refracted
what is the hearing range for humans?
20-20 000 Hz (hertz)
speed of sound in air practical
equipment:
-Two humans
-One balloon
-One stopwatch
-Trundle wheel
speed of sound in air practical
method:
-Measure the distance between person 1 and 2 using a trundle wheel
-Person 1 pops the balloon
-Person 2 starts the stopwatch when balloon is popped
-repeat 3x and calculate an average
speed of sound in air practical
(what do you do to improve accuracy) 2 points
-two people swap ends to counter any wind effects
-Move further away from each other to make the reaction of time more accurate
pitch in terms of frequency..
the higher the frequency, the higher the pitch
sound in terms of amplitude…
the higher the amplitude, the louder the sound
