WAVES

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WAVES

• A wave is any disturbance that transfers energy
  through matter or space.

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WAVES

• WAVES carry energy

• WAVES do work

• WAVES transfer energy by vibrating particles
  through a medium.

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MEDUIM

• A medium (media) is any substance through which a
  wave can travel. Media can be a solid, liquid, or
  gas.
• Particles vibrate then pass that energy onto the
  next particle and so on and so on thus creating a
  wave.

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MECHANICAL WAVES

• Mechanical waves require a medium.
• Sound waves travel by vibrating particles in
  solids, liquids, or gases.
• If you put an alarm clock in a vacuum
• you will cease to hear the alarm.
• Examples of mechanical waves are
• sound waves
• ocean waves
• seismic waves

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ELECTROMAGNETIC WAVES

• Do not require a medium to transfer energy.
• Travel through empty space
• Examples are
• visible light waves
• microwaves
• television/radio signals
• xrays

• Can travel through substances such as water, air,
  glass
• But travel fastest through empty space (a vacuum)

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Types of Waves

• Longitudinal waves
• Particles vibrate in the same direction as the
  wave is traveling.
• A sections of a longitudinal wave where the
  particles are crowded together are called
  compressions.
• The sections where particles are less crowded is
  called a rarefaction.
• Sound waves are longitudinal waves.

• Transverse Waves
• Particles vibrate up an down.
• Particles move perpendicular to the direction the
  wave is traveling.
• Highest point is called the crest.
• Lowest point between two crests is called a
  trough.
• Electromagnetic waves are transverse waves even
  though they do not vibrate particles in a medium.

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SURFACE WAVES

• When waves occur at or near the boundary between
  two media, traverse and longitudinal waves can
  combine to form surface waves.

• Ocean waves are surface waves.
• Surface waves look like transverse waves but
  particles in the medium of a surface wave move in
  circles rather than up and down.
• The particles move forward at the crest of the
  wave and backwards at the trough.

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PROPERTIES OF WAVES

• AMPLITUDE
• Property of a wave related to the height of the
  wave.
• Larger Amplitude means more energy.

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PROPERTIES OF WAVES

• FREQUENCY
• Frequency is the number of waves made in a given
  amount of time.
• You can measure frequency by counting the number
  of crests or troughs that pass a point in a
  certain amount of time.

• WAVELENGTH
• Wavelength is the distance between any point on a
  wave and the next corresponding point on the
  wave.

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PROPERTIES OF WAVES

• Higher Frequency means more energy
• If two amplitudes are equal in height, high
  frequency waves carry more energy than low
  frequency.

• Frequency and wavelength are related.
• A wave with a short wavelength carries more
  energy than a wave with a long wave length.

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PROPERTIES OF WAVES

• Wave Speed
• Speed is the distance traveled over time.
• Wave speed (v) is found by measuring the distance
  a single point on a wave travels in a given
  amount of time.
• Wave speed can be expressed by the following
  equation
• V ? X f
• where
• ? is the greek symbol lambda and represents the
  wave length.
• f is the frequency of the wave.

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MATH FOCUS

• Determine the speed of a wave that has a
  wavelength of 5 meters (?) and a frequency of 4
  Hz (f). Step one write the equation for wave
  speed.
• V? X f
• Replace the ? and f with the values given in
  the problem, and solve.
• v 5 m X 4 Hz Remember 1 Hz 1/s
• v 5 m X 4(1/s)
• v 20 m/s

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• The equation for wave speed can be rearranged
  to find wavelength and frequency.
• Wavelength formula
• ? v/ f
• Frequency Formula
• fV/ ?

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WAVE INTERACTIONS

• Refraction
• Is the bending of a wave as it passes at an angle
  from one medium to another.
• Waves speed varies depending on the medium
  traveled through.
• When a wave enters a new medium at an angle the
  part of the wave entering first travels at a
  different speed than the rest of the wave.

• Reflection
• Occurs when a wave bounces off an object.
• All waves can be reflected.
• Reflected sound waves are called echos.
• Light waves reflecting off an object allow you to
  see the object.

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WAVE INTERACTIONS

• Diffraction
• Is the bending of waves around a barrier or
  through an opening.

• Interference
• When two or more waves overlap.
• Matter can not occupy same space at same time,
  energy can.
• Waves are energy.
• After two waves interfer they continue traveling
  in the same directions.

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INTERFERENCE

• Constructive Interference
• Happens when crests of one wave overlap the
  crests of another wave.
• When this happens a new wave with higher crests
  and deeper troughs is formed. The new wave has a
  larger amplitude.

• Destructive Interference
• Happens when the crests of one wave and the
  troughs of an other wave overlap.
• The new wave has a smaller amplitude than the
  original waves.

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emotion.html