Introduction to Waves (PHYISCS 2)

• What Are Waves?

  • Is a disturbance that carries energy through matter or space without transferring matter.
• Amplitude

  • The greatest distance from equilibrium.
• The bigger the amplitude of the wave, the more energy it has.
• Crest

  • The top point of the wave.
• Trough

  • The bottom point of a wave.
• Wavelength

  • The shortest distance between points where the wave pattern repeats itself.
  • It is measured in meters, the symbol is λ
• Phase

  • Any two points on a wave that are one or more whole wavelengths apart
• Frequency

  • Is the number of complete oscillations a point on that wave makes each second.
  • Is measured in Hertz (Hz).
• Speed

  • or velocity of a wave is how fast the energy is moved.  For most waves, wave speed does not depend on amplitude, frequency, or wavelength.  Speed depends only on the medium through which it moves.
• Period

  • The time it takes to go through one cycle, or the time it takes a point to go through one phase of the wave.
  • The period of this is measured in seconds, and its symbol is “T”.
• Transverse Waves

  • A wave that disturbs the particles in the medium perpendicular to the direction of the wave’s travel.
• Longitudinal Waves:

  • A wave that disturbs the particles in the medium parallel to the direction of the wave’s travel.
• Within longitudinal waves, regions in which the particles are relatively close together are called compressions, and regions where they are relatively far apart are called rarefactions.
• Constructive Interference

  • When the crest of a wave meets the crest of another wave of the same frequency at the same point.
• Destructive Interference

  • When the crest of a wave meets the trough of another wave of the same frequency at the same point.
• Different Amplitude

  • All other scenarios of wave interference.
• Nodes and Antinodes

  • are used to help describe and understand waves
• Node

  • is where zero displacement of the medium can be observed. (No displacement)
• Antinode

  • is where the largest displacement of the medium can be observed.(Anti no displacement)
• Sound Wave

  • a longitudinal wave that is caused by vibrations and that travels through a material medium.
• • The speed of sound depends on the medium.
  • The speed of sound in a particular medium depends on how well the particles can transmit the motions of sound waves.
• Pitch

  • is determined by frequency.
• Pitch

  - is a measure of how high or low a sound is perceived to be, depending on the frequency of the sound wave
• Infrasound

  • Any sound with a frequency below the range of human hearing
  • slow vibrations of frequencies lower than 20 Hz
• Ultrasound

  • Any sound with a frequency above the human hearing range
  • Any sound wave with frequencies higher than 20,000 Hz
• How do musical instruments make sound?

  • Most instruments produce sound through the vibration of strings, air columns, or membranes.
• Instruments use resonance to amplify sound.
• Resonance

  • a phenomenon that occurs when two objects naturally vibrate at the same frequency
• Natural Frequencies

  • the specific frequencies at which an object is most likely to vibrate.
• • The natural frequency of an object depends on the object’s shape, size, mass, and the material from which the object is made.
• The human ear is a sensitive organ that senses vibrations in the air, amplifies them, and then transmits signals to the brain.
• Equilibrium

  • balance without the presence of force
• Oscillations

  • motion of a system that predictably occurs in a repetitive manner
• Decibel

  • Measurement of sound intensity