Waves Notes Part 1

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Waves Notes Part 1
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Wave

• Disturbance that moves through matter or space.
• Carry/transfer energy from one place to another.

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2 Main Types

• Electromagnetic
• Mechanical

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Electromagnetic

• Waves that can travel through matter or empty
  space where matter is not present. (also called a
  vacuum)
• Examples radio waves, microwaves, infrared rays,
  visible light, ultraviolet (UV) rays, and x-rays
  all travel as electromagnetic waves
• General structure (transverse waves)

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Mechanical

• Require the particles of the medium to vibrate in
  order for energy to be transferred.
• Sound waves, as with all mechanical waves, CANNOT
  be transferred or transmitted through empty space
• Examples Water waves, earthquake/seismic waves,
  and sound waves
• Structure transverse OR compressional

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• Transverse Wave
• Waves which vibrate by moving back and forth and
  perpendicular (at right angles) to the direction
  the wave travels are called transverse waves.
  Ex Secondary Waves, Electromagnetic waves
• Electromagnetic are double transverse waves
  because they are made of electric and magnetic
  fields
• Pick a single particle and watch its motion.

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Compressional Waves

• Compressional waves are mechanical type waves
• Vibrate by pushing together and moving apart
  parallel to the direction in which the wave
  travels (Aka longitudinal) Ex Primary Waves
  Sound waves
• Pick a single particle and watch its motion.
• Particles move from left to right.

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• Some waves are both transverse and compressional
• Water waves and surface waves (seismic ) are
  examples of waves that involve a combination of
  motions.
• Look at the two particles in blue to show that
  each particle travels in a clockwise circle as
  the wave passes.

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Transverse Waves
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Properties of Waves

• A.) FREQUENCY
• Waves are measured in hertz.
• Measure of how many waves pass a point in a
  certain amount of time
• The higher the frequency Shorter wavelength,
  greater energy carried

Higher Frequency Lower Frequency
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• B.) AMPLITUDE
• Measures of the distance between the middle of a
  wave and a crest or trough
• For Light the greater amplitude the brighter the
  light.
• Sound greater amplitude the louder it is
• The Amplitude of a wave is related to the energy
  which it transports.

Lower Amplitude
Greater Amplitude
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Properties of Waves

• C.) WAVELENGTH
• Measure of distance from crest to crest or trough
  to trough (transverse)
• A higher frequency causes a shorter wavelength
  and greater energy

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Compressional

• Label rarefaction and compression

Rarefaction
Compression
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Compressional
Transverse
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Properties of Waves

• A.) WAVE SPEED
• The distance a wave travels in an amount of time
• Wave speed is determined by two things
• Type of wave
• Nature of the medium (material)
• Electromagnetic waves (including light) travel at
  the same speed in empty space (vacuum) which is
  (3 x 108 m/s)
• Travel slowest in solids/liquids
• Travel fastest in air/gas

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B.) Color Filters

• Write see color notes

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• C.) REFLECTION
• When a surface (mirror or object) that doesnt
  absorb or transmit light.
• -(Bounces off)
• -Or sometimes the surface will absorb some light
  and reflect the rest. Examples Banana-reflects
  yellow absorbs all other colors, Leaf-reflects
  green and absorbs all other colors.
• Light waves reflected off a mirror
• Sound waves echoes (used by bats and dolphins
  to communicate)

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Reflection of Waves
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• D. REFRACTION
• When light passes through a different medium and
  bends because it is changing speeds.
• Examples
• P-waves entering the Outer Core
• Rainbows formed as light travels through rain
  drops
• Pencil looking bent in water
• Light traveling through a prism

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Refraction of Waves
DRAW THIS
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• E. DIFFRACTION
• When light bends around an opening
• Examples
• Light waves bend under doors or through windows
• Sound waves bend through open doors and go down
  hallways.

Brain Pop on Refraction and Diffraction
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Diffraction of Light Waves