Science

• Mechanical Waves - disturbances in matter that propagate and form moving patterns in the process.
• Matter - is called the medium in which mechanical waves propagate.
• Electromagnetic Waves - the disturbances that can propagate and form moving patterns even in the absence of matter.
• Electromagnetic Waves travels through vacuum with the same speed of light.
• An electromagnetic wave is an oscillating electric and magnetic field
• Mechanical Waves - can be classified according to how the particles in the medium move relative to the movement pattern.
• Transverse Wave - if the motion of the particles in the medium is along a line perpendicular to the direction of the moving pattern
• Longitudinal Wave - if the motion of the particles in the medium is along a line parallel to the direction of the moving pattern.
• Water Waves are transverse waves since the particles in water move up and down as the pattern moves horizontally
• Point of Wave

  • crest - highest point of wave
  • trough - lowest point of wave
  • midpoint - symbolized by the straight broken line
• amplitude - the height of the wave, which is measured from the midpoint position to either the crest or the trough of a wave
• wavelength - is the distance between the succeeding identical parts of the wave
• Lambda - symbol used for wave length
• frequency - shows how frequent a vibration takes place
• hertz - unit of measurement per second
• (f) - symbol for frequency
• Heinrich Hertz - a german physicist who validated the existence of radio wave length in 1886
• 1 Hz = 1 vibration
• Higher unit of frequency

  • kHz - Kilohertz
  • mHz - Megahertz
  • gHz - gigahertz
• Period - is the time it takes to complete one vibrational cycle or one complete wave
• (S) second - its unit of measurement
• Wave Speed - is the speed of wave as it travel
• Wave - is a disturbance that that carries energy to one place to another
• Medium - a wave can move through matter
• if a wave needs a medium its Mechanical Wave
• If a wave does not need a medium, Electromagnetic Energy
• Sound - gives us auditory information
• Classification of Sound

  • Mechanical
  • Longitudal
• Hearing - one of our senses
• Eardrum - vibrates when sound waves reaches it
• cochtea - a snail - shaped structure, is connected to the auditory nerve
• Audible Sounds - human can hear sounds with frequencies between the range of 20Hz up to 20Htz
• Infrasonic Sound - is a form of low frequency sound that human ears cannot detect
• Ultrasonic Sounds - the higher frequency of inaudible sounds, which is more than 20 kHz
• Echo - is a seperated sound because the sound wave is reflected back to the source as it hits the surface
• Echolation - means using sound waves and echo to detect objects occupying space
• Common Properties of Sound

  • Loudness
  • Pitch
  • Quality
• Light - is a form of energy, used by plants for photosynthesis
• Sources of Light

  • Artificial Light
  • Natural Light
• Isaac Newton - a mathematician and physicist, thought that shadows were proof that light is made up of particles called corpuscles