Wave Amplitude

Wave Properties

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Parts of a Wave

Amplitude, Wavelength, Frequency, Wave Speed

All waves have these properties, regardless of their classification

Draw

Label the wavelength and amplitude of the wave

Amplitude

• Amplitude is the maximum distance the particles vibrate from the rest position.

• Rest position is the place where the particles of a medium stay when there is no disturbance. The taller the wave = larger amplitude

• The taller the wave = larger amplitude

Poll

If a wave has a small amplitude, do you think it has low energy or high energy?

• Low energy

• High Energy

Amplitude & Energy

• Small amplitude = low energy

• Large amplitude = high energy

Measuring Amplitude on a Transverse Wave

• Measured from the rest position to the crest or trough of the wave

Measuring Amplitude on a Longitudinal Wave

• It is difficult to show amplitude on this wave.

• Amplitude of a longitudinal wave is related to how tightly packed the compressions are.

• The tighter the packing = greater amplitude

Draw

Circle the wave with more energy

Wavelength

• Wavelength is the distance from any point on a wave to an identical point on the next wave

Wavelength on Transverse Waves

• The distance between two adjacent crests

• OR the distance between two adjacent troughs

Wavelength on Longitudinal Waves

• The distance between two adjacent rarefactions

• OR the distance between two adjacent compressions

Wavelength & Energy

• The shorter the wavelength the greater the energy

• OR the longer the wavelength the lower the energy

• They are inversely proportional

• The symbol for wavelength is the Greek letter lamda--> λ

Draw

Circle the wave with the longest wavelength

Frequency

• The number of vibrations (waves, cycles) that occur per second

• Unit is Hertz (Hz)

• 1 Hz = one wave per second

• High frequency carry high energy

Frequency in Transvese Waves

• Frequency is measured by the number of crests OR troughs that pass a certain point over a certain amount of time

Frequency in Longitudinal Waves

• To find the frequency, count the number of compressions or rarefactions.

Multiple Choice

Which wave carries more energy?

• Wave A

• Wave B

Wave Speed

• Wave speed is the speed at which a wave travels

• The speed depends on the medium in which the wave is traveling

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• Wave speed = wavelength x frequency

Multiple Choice

If a wave has a frequency of 2 waves / second and a wavelength of 20 cm/wave, what is the wave speed?

wave speed = wavelength x frequency

• 10 cm/s

• 2 cm/s

• 20 cm/s

• 40 cm/s