### motion | wave:

Sound wave
* All sound waves travel at the same speed in the same medium.
* Most sound waves move through substances
  - transfer energy
* Most sound waves travel further from the axis
  - through water
* Some sound waves are produced by sound.
* Some sound waves cause damage
  - internal damage
* Some sound waves cause massive damage
  - vibration
  - have energy
  - hit eardrums
  - move through air
* Some sound waves travel through air
  - warm air
* are a disturbance or vibration in a medium of solid, liquid, or gas
  - form of radiant energy
  - regular variation in air pressure
  - series of compressions and rebounds of the medium through which it is traveling
  - actually waves of changing pressure
  - also sine waves
* are an example of longitudinal waves
  - pressure waves and they can move through gases, liquids and solids
* are compression waves associated with the potential and kinetic energy of air molecules
  - that move back and forth parallel to the direction of the wave
  - elastic waves that propagate in a fluid or solid
  - important in our daily lives
  - incapable of traveling through a vacuum
  - inherently analog
  - instead the oscillating compression of molecules
  - introduced into a medium by the vibration of an object
  - just like the waves in an ocean because it's the same scientific principle
* are like light and water waves in other ways too
  - little pushes of air
  - located in air
* are longitudinal waves produced by variations in air pressure
  - waves, light waves are transverse
  - louder when the amplitude is higher
  - made up of kinetic energy
  - necessary for hearing and a light for seeing
  - nothing more than waves of pressure, pushing in one direction and then the opposite
  - produced by vibrating objects
* are rapid changes in magnetic fields
  - the attractions between molecules
  - sinusoidal in shape
  - spherical and three-dimensional
* are the result of mechanical vibration
  - unseen way sound travels through the air and meets our ears
  - transmissible in liquid and solid
  - variations in air pressures above and below the ambient pressure
  - very low frequency radio waves
* are vibrations in matter
  - transmitted through matter
* behave in a similar manner.
* bend towards a region of minimum sound velocity due to refraction.
* bounce back reflections of any density change.
* bouncing off submarines sound different from waves ricocheting off rocks or animals.
* bring music to our ears and light waves bring energy from the sun.
* can behave like light, too
  - create high-energy bubbles in liquids
  - identify defects in airplanes, bridges, and pipelines
  - reflect off of surfaces, redirecting the waves creating an echo
  - travel through solids, liquids and gases
* carry energy through gasses, like air, and through some liquids and solids.
* cause each fly eardrum to beat out of phase with the other
  - fine hairs in the inner ear to vibrate generating nerve impulses
* cause the diaphragm to vibrate at the same frequency as the sound waves
  - eardrum to vibrate, setting the three small bones in motion
  - eardrums to vibrate
* come in through the outer ear and set the tympanum in vibration.
* correspond to pressure fluctuations that alternate above and below atmospheric pressure.
* create rapid oscillations that disrupt collagenous fibers and increase cell metabolism.
* define the characteristics of the breast abnormality.
* differ from water waves in that the wavelengths involved are much shorter
  - waves in a string in a fundamental way
* do show interference.
* echo to form an image on a computer screen.
* enter the ear canal and vibrate the ear drum
  - ear, and are then amplified
  - outer ear through the external auditory canal, or pinna
* exert some force on particles.
* exist as variations of pressure in a medium such as air.
* funnel into the outer ear and travel down the ear canal to the eardrum.
* have a wavelength , which is the physical distance between compression pulses
  - energy and are measured in decibels
* lose energy as they travel.
* made by large fractures go through the ice and penetrate into the ocean.
* make minute vibrations on the surface of water
  - the ear drum vibrate
* move the air and hit the ear drum much as the wind hits a sail
  - ribbon which changes the current flowing through it
* originate from the vibrations of the double reed.
* pass through the skin into the body.
* passing through the liquid cause the bubble to compress and expand repeatedly.
* penetrate flesh to some extent.
* propagate freely in the electromagnetically opaque ocean
* pulsate through the solution to dislodge particles from the wafer.
* reach our ears after multiple reflections.
* reflect off of large objects, like sound walls.
* refract as they cross between layers of water with different densities.
* require a medium to travel.
* ripple out in all directions from the sound source, gradually losing energy.
* strike the eardrum, sending vibrations to the middle ear
  - fish's inner ear
* transfer energy from the singer to the glass
  - the energy of the source to the medium around it
* travel about four times as fast in water and about ten times as fast in steel
  - by alternately squeezing and stretching the air
* travel down a canal in the ear and reach the eardrum
  - the ear canal and hit the eardrum in the middle ear
  - easily in a clear fresh water environment, such as most inland lakes
  - fastest in solids, slower in liquids and slowest in air
  - in much the same way in liquids and solids as in air
* travel more easily through liquids
  - slowly through air than through any other medium
  - one mile in about five seconds
* travel slower in bubbly water than in either water or air
  - cooler air than they do in warmer air
* travel through air in much the same way as water waves travel through water
  - gases, solids or liquids
* travel through the air by vibrating or moving the particles of matter in the air
  - in a similar manner, but in all three dimensions
  - atmosphere by vibration
  - outer ear to the eardrum to get to the middle ear
  - until hitting an object and bouncing back
  - up to five times faster through water than through air
  - when the vibrating stuff causes stuff surrounding it to also vibrate
* traveling through air of uneven temperatures are bent from warm air toward cool air.
* type of wave which has a medium of air.
* use the matter to move the vibrations.
* used in diagnostic medicine are harmful.
* vibrate the eardrum in much the same way.
+ Sound recording, Technology, Tape
  * In the late 1930s the tape recorder appeared. Tape recorders use a magnetic tape as a medium, with a 'recording head' to store the sound on the tape. Sound waves are converted into an electrical signal inside the recorder. This signal goes into the head, where it changes the polarity of very small magnets. Tape moves past the head at a constant speed, and its magnetic particles are rearranged by these magnets to a pattern that represents the sound wave. These magnetic patterns are much like the small grooves of a cylinder or disc record in the way that they represent the vibration energy of sound waves.
+ Sound, Sound, Compression and rarefaction:
  * Rarefaction is the part of the waves where the molecules are far away from each other. Sound waves are a lot of compressions and rarefactions.