sound and waves

• a sound is made when an objects moves up and down fast, its called vibrating
• particles between the vibrating object and our ear must also vibrate
• waves are vibrations or oscillations that transfer energy but not matter
• -the crest is the top of the wave and the trough is the bottom

  -the amplitude is the distance from the top of the wave to the middle

  -the wavelength is the distance from the one point on a wave to the same point on the next wave

  
• frequency is the number of waves that go past one point each second
• frequency is measured in Herts (Hz)
• long itusinal waves have vibrations parallel (in the same direction) to the direction of energy transfer
• a loud sound has more energy so the vibrations are bigger
• a higher pitched sound has a sound has a higher frequency because it vibrates faster so there are more waves per second
• a loud sound has a bigger amplitude because it transfers more energy so the vibrations are bigger
• a higher pitched sound has a higher frequency because it vibrates faster so there are more waves per second
• inside of the human ear

  
• auditory nerve takes nerve impulses to the brain
• cochlea turns vibrations into nerve impulses
• eardrum vibrates when sound wave reachs it
• pinna is the external structure of the ear
• auditory canal channels sound into the ear
• ossicles pass on the vibrations and amplify them
• echo is the reflection of a sound
• speed of light = 300,000 km/sec
• speed= distance/time (m/s)
• time= distance/speed of light (s)
• distance= speed x time (m)
• All elctromagnetic waves are transverse waves, can travel throug vacuum (space), and travel at the speed of light (~300,000,000m/s)
• the electro magnetic spectrum

  
• the list of the electromagnetic spectrum is in order of increasing wavelength
• electromagnetic radiations can have a damaging effect on the body or can ionise atoms which can cause cancer
• as the frequency increases the wavelength gets smaller
• ultra violet, x-rays and gamma rays are so small that they can interact with cells, DNA and atoms causing damage. This is called Ionising Radiation
• sound transfers energy
• sound is produced by vibrations