WAVES

• Waves - can be described as a disturbance that travels through a medium from one location to another location
• Disturbance - an alteration or displacement of a region of a medium from its equilibrium state.
• Pulse - is a single disturbance moving through a medium from one location to another location.
• Crest - maximum upward displacement
• Trough - maximum downward displacement
• Amplitude - distance from equilibrium state to its peak
• Wavelength - distance from crest to crest & trough to trough
• Crest - maximum amount of positive or upward displacement from the rest position.
• Trough - maximum amount of negative or downward displacement of a particle on the medium from its rest position.
• Wavelength - length of one complete wave cycle.
• Lambda

  
• Frequency - how often the particles of the medium vibrate when a wave passes through a medium.
• Period - the time for a particle on a medium to make one complete vibrational cycle.
• Cycle - is a complete vibration
• Transverse Wave - wave in which particles of the medium move in a direction perpendicular to the direction that the wave moves.
• Longitudinal Wave - wave in which particles of the medium moves in a direction parallel to the direction that the wave moves.
• Electromagnetic Waves - a wave that is capable of transmitting it energy through a vacuum. Are produced by the vibration of charged paarticles.
• Mechanical Waves - a wave that is not capable of transmitting its energy through a vacuum.
• What type of wave requires a medium in order to transport their energy from one location to another?

  Mechanical Wave
• Sound - vibrations that travel through the air
• Propagation - the result of such longitudinal vibrations is the creations of compressions and rarefactions within the air.
• Compression - region in a longitudinal wave where particles are closest together.
• Rarefaction - particles are furthest apart
• Pitch - the sensation of a frequency
• Infrasonic - Below 20 hertz
• Ultrasonic - above 20,000 hertz
• How many hertz is an audible sound that can hear by human?

  21 hertz - 19,999 hertz
• Ears - transducer
• Supersonic - not related to the frequency but to the velocity of sound.
• Created by Supersonic

  • Sonic Boom
• Intensity - The amount of energy that is transported past a given area of the medium per unit of time.
• Reverberation - is a prolongation of sound in a hall even though the source of sound is cut off.
• Echoes - It occurs when a reflected sound waves reaches the ear more than 0.1 secs
• Reverberation - reflected sounds to die down by 60 decibels
• Reflected sound tend to "build up" to a level louder that direct sound. Reflected sound MASK direct sound
• Late arriving reflections tend to SMEAR the direct sound signal
• Sonar - sound navigation and ranging
• Decibel - unit of measurement which is used on how loud a sound is
• Loudness - is the human perception of the intensity of sound (as dissipated at the eardrum)