What do these pictures have in common?. 2 Introduction to Waves.

What do these pictures have in common?

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Introduction to Waves

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Waves are everywhere in nature

Sound waves visible light

wavesradio wavesmicrowaveswater waves

telephone chord waves

stadium waves earthquake

waves waves on a

stringslinky waves

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What is a wave?

A wave is a disturbance (source of energy) that travels through a medium from one location to another.

A wave is the motion of a disturbance

Waves transfer energy not matter. The water waves below are carrying energy but are not moving. Waves can only exist as they have energy to carry.

Mechanical Waves

Waves that require a medium to pass through.

A medium is a material through which waves can passGases (air)Liquids (water)Solids (ropes)

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What are two kinds of mechanical waves?

TransverseLongitudinal (Compression)

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Transverse Waves

A disturbance that is perpendicular to the direction of the wave

Ex. Moving a rope up and down.

disturbance

wave direction

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Example of a transverse wave:

Longitudinal (Compression) Wave

The disturbance is parallel to the direction of the wave travel. Ex. Spring toy or SLINKY!

Compression-the coils come together

Rarefaction- the coils spread out

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Example- Longitudinal Wave

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Longitudinal vs. Transverse Waves

The differences between the two can be seen

Properties of Waves

Crest and TroughAmplitudeWavelengthFrequency

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Crest and Trough

Crest-The highest part of a transverse wave

Trough- The lowest part of a transverse wave

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Amplitude-Transverse Wave

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Amplitude- Longitudinal WaveDepends on how dense (bunched) the

medium is at each compression.Coiled spring A has the greater

amplitude.

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Wavelength

The distance between two corresponding parts of a wave.Crest to CrestTrough to Trough

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FrequencyThe number of complete waves that pass

a given point in a certain amount of time.Measured in hertz (Hz)

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HIGH Frequency

LOW Frequency

Review

1. Identify two types of mechanical waves.

1. What is amplitude?

1. If a wave has a high frequency, do the wavelengths become shorter or longer?

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