Download - 2.6 what is a wave
What is a wave?
28 January 2015
How many types of wave have you
heard of in everyday use?
Do they have anything in common?
Aims
• Describe the origin of a wave
• Explain the properties of a wave
Key terms
• Displacement: how far the wave is disturbed from its rest position
• Oscillation: a complete to and fro movement; this could be going up and down or sideways
What is a wave?
A wave is a disturbance
moving through a material
What causes a wave?
• The source of a wave is always something that vibrates
• The material that the wave travels through is called the medium
Amplitude, A
• The maximum distance that each point in the medium moves from its normal position as the wave passes
• Measured in metres, m
Frequency, f
• This is the number of waves that pass any point in the medium every second, so it is the same as the number of vibrations per second
• Frequency is measured in per seconds or hertz, 1/s, s-1 or Hz
Wave speed, v
• This is the speed at which each wave crest moves through the medium.
• Measured in metres per second, m/s or ms-1
Wavelength, λ
• This is the length of a complete wave measured from any point to the next identical point – the distance is always the same no matter which point you choose
• It is measured in metres, m
Wavelength, λ
• This is the length of a complete wave measured from any point to the next identical point – the distance is always the same no matter which point you choose
• It is measured in metres, m
fv Where:v = speed of wave / m/sf = frequency of wave / Hz (1/s)λ = wavelength of wave / m
How can we prove this?
1
1
330
330
msf
msv
fv
What would happen if we increased the wavelength of a wave?What would happen if we decreased the wavelength of a wave?
Assessment activity 2.6
• Discuss how you could model the movement of a wave (P3)
• Construct your model or role play it to another group
• REMEMBER: the longer the wavelength, the smaller the frequency. When calculating speed, make sure you change the prefixes