Please enable JavaScript.
Coggle requires JavaScript to display documents.
Waves - Coggle Diagram
Waves
Sound waves
-
-
The vibrations mean that sound waves travel in a series of rarefactions and compressions - longitudinal wave
Ears
Our ears detect vibrations and are sensitive to a range of frequencies between 20Hz and 20,000 Hz
-
Ultrasound - frequencies above 20,000 hertz used for scans of foetus
Speed
Liquids
Liquids are more rigid and less compressible than gases so speed of sound in liquids is much higher than in gases
-
-
Sound needs to travel through a medium - more rigid the medium is, higher the speed of sound wave through the medium
Sound waves cannot travel in outer space because it is a vacuum therefore no particles are there for sound to vibrate
uses
Ultrasound
When ultrasound waves meet a boundary between two different materials, some are reflected
-
A computer processes the timing and distribution of these waves and provides a video image of the foetus (or broken bones etc...)
-
-
-
-
-
-
Waves at a boundary
When waves travel from one medium to another their speed and wavelength change but frequency stays constant
-
Speed and wavelength change when travelling from one medium to another - they are directly proportional
If the speed doubles, wavelength doubles
If speed halves, wavelength halves
Waves can be reflected, refracted, absorbed and transmitted at the boundary between one medium and another
Absorbtion
When waves meet materials, energy can be abosrbed
-
-
Refraction
If the wae crosses to the new medium at an angle the change in waves speed will cause the direction of it's motion to change and the wave will appear to bend
-
-
Measuring waves
-
Wavelength
Distance between two adjacent wave fronts - e.g in transverse the distance between two peaks of adjacent waves
-
-
Rp9
equipment
-
-
-
Transparent blocks made from differing materials; plastic, glass...
-
-
method
- Put the slit into the ray box and turn it on to produce a narrow ray of light
- Place the first block of material on top of a piece of paper and trace around it
- Draw a normal at 90 degrees to the block and align the incident ray between the normal and block
- Draw the reflected ray and refracted ray - remove the block and draw a straight line between point of reflection and refraction
- using a protractor measure: angle of incidence, angle of refraction and angle of reflection
-
-
Earthquakes
P - waves
These are longitudinal, seismic waves
-
S - waves
These are transverse, seismic waves
-
Uses of seismic waves
-
-
By detecting seismic waves from earthquakes it has been worked out that there is a solid core surrounded by a liquid outer core
-
-