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Waves Waves as energy Types of waves Parts of a wave Movement of waves Properties of waves

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Page 1: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

WavesWaves as energyTypes of wavesParts of a wave

Movement of wavesProperties of waves

Page 2: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

What exactly is a wave?• Definition: A wave is any disturbance that

transmits energy through matter or space• Waves move through matter but they do

not move the matter itself

• Ocean waves• Sound waves• Light waves• Radio waves• Microwaves• Earthquake seismic waves

Page 3: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

So how are these waves different?

• Waves can travels through a medium ( ex. water, ground, air)

• Mechanical waves need a medium

• Electromagnetic waves do not need a medium

Page 4: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

Types of Waves

• Particles in a transverse wave vibrate in an up and down motion perpendicular to the wave direction.

• Particles in a compressional wave vibrate back and forth in the same direction that the wave travels.

• At the boundary between two media transverse and longitudinal waves can combine to form surface waves.

Longitudinal and Transverse Wave Motion

Animation courtesy of Dr. Dan Russell, Kettering University

Page 5: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

Parts of a WaveCrest: the highest point

Trough: the lowest point

Page 6: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

Amplitude is the height of a wave is and how much energy it is carrying.

The wavelength is the distance between crests

Properties of Waves

Wave simulator courtesy of National Geographic Website

Page 7: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

Compressional Waves

Compression: is an area in a wave where the particles are closer together.

Page 8: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

Compressional Waves

Rarefaction is an area in a wave in which the particles are spread further apart.

Page 9: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

More Wave Properties

Frequency (f) is the number of waves that pass a point in a given time, and measured in hertz. A period (p) is the inverse of frequency = 1/f

(time for one wave to pass)

1 2 3

Page 10: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

More Wave Properties

The wave speed is measured as distance divided by time. But it can also be calculated by multiplying wavelength by frequency.

1 2 3

Page 11: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

More Wave Movement…• When waves bounce off something is

it called reflection. • A reflected sound wave is called an

echo.• When a wave is bent at an angle as it

passes through a new medium it is called refraction.• When a wave is bent around a barrier or

an opening it is called diffraction

Page 12: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

• When an object or wave hits a surface through which it cannot pass, it bounces back.

- Interactions of Waves

Reflection

Page 13: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

- Interactions of Waves

Refraction• When a wave enters a new medium

at an angle, one side of the wave changes speed before the other side, causing the wave to bend.

Page 14: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

- Interactions of Waves

Diffraction• When a wave moves around a barrier

or through an opening in a barrier, it bends and spreads out.

Page 15: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

When Waves Interfere with each other…

• Interference is when two waves overlap. They can overlap and make a larger wave, they can also cancel each other out.

Page 16: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

Interference• The interference that

occurs when waves combine to make a wave with a larger amplitude is called constructive interference.

The interference that occurs when waves combine to make a wave with a smaller amplitude is called destructive interference.

Page 17: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

- Interactions of Waves

Standing Waves• If the incoming wave and a reflected

wave have just the right frequency, they produce a combined wave that appears to be standing still.

Page 18: Waves Waves as energy Waves as energy Types of waves Types of waves Parts of a wave Parts of a wave Movement of waves Movement of waves Properties of

More Wave Properties…

• When the vibrations of one object cause another nearby to vibrate…that is Resonance.

• Some musical instruments use resonance to produce sound, like a marimba.