Sound is longitudinal Wave
- sound waves squash and stretch particles
- Compresion are parts of the wave under high pressure
- rarefractions are the parts under low pressure
- a full wave length is from one compresion to another
- the amplitude shows how much energy the wave is carrying ( how loud it is)
In longitudinal waves the vibration are along the same direction as the wave is travelling. Whereas in a transverse wave the vibrations are 90 degrees to the direction of the wave.
Uses of Ultrasound
- Ultrasound is higher frequency than we can hear ( above 20000 hz)
However it has many useful medical properties
- Breaking down accumulations in the body such as kidney stones by using high energy waves that turn the mass into a sand like substance (the waves cause vibrations and osilations).
Body scanning- Ultra sound waves pass through the body but when the reach a different substance e.g. skin and fluid some of the wave is reflected back. The timing and the distribution of these reflection allow a computer to make an accurate reprsentation of what is inside the body
Ultrasound also has it's advantages over X-RAY
- It is safer as it does not harm living cells and it is not ionising unlike X-RAY waves
- Also it can be used to scan soft tissue whereas X-RAY can only scan harder things such as bone. As it is more penetrating.