3b) Properties of waves

Different types of waves:

Longitudinal waves- The vibrations are along the SAME DIRECTION as the wave transfers energy
                          Examples- sound, ultrasound, shock waves and slinky spring has compressions when pushed

Traverse waves- The vibrations are at 90 degrees to the DIRECTION ENERGY IS TRANSFERRED by the wave
               Examples- light, all other EM waves, waves on strings, ripples on water and slinky spring goes up and down

Wavelength (λ)- is the distance from one peak to another
Frequency (f) - is how many complete waves there are per second. Measured in hertz (Hz)
Amplitude- is the height of the wave (from rest to crest)
Speed (v) - how fast it goes
Period (T) - the time taken for a complete wave to pass a point

Wave transfers energy and information without transferring matter:

• All waves carry energy in the direction they travel e.g. microwaves 
• waves can also be used as signals to transfer information form one place to another e.g. radio waves through the air 

Wave Speed = Frequency x Wavelength 

v = f x λ

Frequency and time period

f = 1/time period

Paper Two- Diffraction:

Is the spreading out of the waves into the area behind a barrier. The effect is the most noticeable when the wavelength is about the same as the gap through which they are moving 

Waves going through a gap that is BIGGER than their wavelength. They DON'T diffract

Waves going through a gap that is SMALLER than their wavelength. They DO diffract

a) No Diffraction- gap is much wider than wavelength 

b) Diffraction only on the edges- gap is a little bit wider that wavelength

c) Maximum diffraction- gap is the same as the wavelength 

When waves encounter obstacles diffraction causes them to bend around the obstacle. The LONGER the wavelength, the MORE they diffract and bend around.