Waves

• Waves


  • Periodic disturbances that moves away from a source and carries energy with it through matter or space
  • Produced through the repetitive motion of an object called "vibration"
• Source of a Wave

  Particles of a material that vibrate alternately
• Waves are continuously produced when the particles of a material continue to vibrate alternately
• Facts about Waves


  • When objects vibrate, its particles also vibrate
  • Waves travel to a certain distance
  • The direction of the wave is affected by the motion of the vibrating object
  • Waves may travel with or without a medium or material
  • Waves carry energy
  • Waves can do work or cause a change to another object
  • The energy carried by waves can be transferred from one object to another
  • The disturbance created by a wave may last for a period of time
  • The disturbance created by a wave depends upon the strength of its source
• Waves may be classified according to


  • Presence or absence of a medium
  • Direction of wave relative to the vibration of particles
• Types of Wave


  • Mechanical wave - a wave that requires a medium to propagate
  • Electromagnetic wave - these are waves that can travel without a medium
• Examples of Mechanical Waves


  • Sound wave
  • Ocean wave/ Surface wave
  • Seismic wave
  • Heat wave
• Transverse wave


  • Propagated through the upward and downward motion of the vibrating object
  • The particles of the medium vibrate perpendicular to the direction of the waves
• Longitudinal waves


  These waves occur when the individual particles of a medium vibrate back and forth parallel to the direction of the waves travel
• Crest


  Describes the highest point of a wave
• Trough


  Describes the lowest point of a wave
• Amplitude


  Describes the maximum displacement of a vibrating particle on either side of its normal or rest position when it passes. It is also the measure of the energy carried by the wave.
• Wavelength


  The distance between any successive identical parts of a wave. In transverse wave, it can be the distance between two consecutive crests or two consecutive troughs of a transverse wave. In a longitudinal wave, it refers to the distance between two consecutive compressions or two consecutive rarefactions.
• Wavelength


  Measured in meters and is denoted by a symbol called "lambda"
• In visible light, the wavelength determines its color. The light having long wavelength is more visible from a distance compared to the light having shorter wavelength.
• The wavelength of a wave

  Determines its wave speed. The longer the wavelength, the lesser the wave speed. The shorter the wavelength, the greater the wave speed.
• Amplitude


  The measure of the energy carried by the wave. The amplitude of a wave is directly proportional to the energy it carries. In a longitudinal wave, the more compressed the particles are, the greater is the amplitude.
• Frequency


  Refers to the number of waves that pass a given point in a certain amount of time. Frequency is measured in units called "Hertz", after the German physicist Heinrich Hertz who discovered radiowaves. 1 Hz = 1 cycle/ second or 1 Hz = 1 wave per second.
• The frequency of light that our eyes can detect is from 4.3 x 10 14 Hz to 7.5 x 10 14 Hz. Light in this range is called visible light.
• Differences of the frequencies in visible light waves


  Account for the different colors we see
• Wavelength is inversely proportional to its frequency


  Lights with longer wavelength have lower frequency. Lights with shorter wavelength have higher frequency.
• The frequency of a sound wave


  Determines the pitch of a sound. High frequency corresponds to high-pitched sound. Low frequency corresponds to low-pitched sound.
• The frequency of a wave


  Determines the amount of its carried energy. High frequency corresponds to high energy. Low frequency corresponds to low energy.
• Period


  The time to make one complete cycle. It is the reciprocal of frequency. It is measured in seconds (s).
• Wavelength


  Is inversely proportional to wave speed, frequency, and amplitude (energy)
• Longer wavelength


  Lesser wave speed, lower frequency, lower amplitude (energy)
• Shorter wavelength


  Greater wave speed, higher frequency, higher amplitude (energy)
• Wave speed


  Is directly proportional to frequency and amplitude (energy)
• Greater wave speed


  Greater frequency, greater amplitude (energy)
• Lesser wave speed


  Lesser/lower frequency, lesser/lower amplitude (energy)
• Wave speed


  Refers to the distance the wave travels per unit time. Wave speed is related to the frequency of the wave and wavelength. In equation, wave speed can be expressed as: Wave speed = frequency x wavelength
• Most periodic waves have sinusoidal waveforms.
• The frequency of light  that our eyes can detect is from 4.3 x 10 14 Hz to 7.5 x 10 14 Hz.