Sound and light

Sound and light

1. Sound is measured in wave lengths!

   • Sound travels in waves!
     • Sound is invisible
       • Sound travels faster in a solid because the particles in a solid are tightly packed and this means that when the particles vibrate it will be easier for them to collide with each other!

2. Sound is slower than light!

   • Sound travels at 340.29 metres per second!

3. Light travels in waves!

   • Light can travel through a vaccum
     • BBC Bitesize - KS3 Physics - Light waves - Revision 1
     • When light hits glass window it refracts!
       • Refraction is when light hits a surface and changes direction. Unless the beam of light hits the object straight on, when this happens the light ray goes straight through and does not get refracted.
   • Light is changed into electricfal pulses inside the eye, the part of the eye that does this is called the retina. The Retina changes the light rays into electrical signals so that the brain can prosses them.
     • The light spectrum is made up of all the colours of the rainbow.
       • White light is made up of all the colours of the spectrum.
         • When white light hits an object all the colours spill out and this reveals all the colours of the spectrum.
           • The red light has the longest light wave.

4. Light travels at 299 792 458 metres per second

5. Humans can only hear between 20 and 20,000 Hz

   • We measure sound in Hertz
     • Ultrasound is sound that is too high pitched for humans to be able to hear
       • Infra sound is sound that is far too low pitch for the human ear to pick up

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