Diffraction
When waves meet a gap in a barrier, they carry on through the gap. However, the waves also spread out to some extent into the area beyond the gap. This bending of the waves is called diffraction.
The amount of diffraction depends on the wavelength and the size of the gap. The smaller the width of the gap compared with the wavelength of the wave, the stronger the diffraction.
When waves meet a gap in a barrier, they carry on through the gap. However, the waves also spread out to some extent into the area beyond the gap. This bending of the waves is called diffraction.
The amount of diffraction depends on the wavelength and the size of the gap. The smaller the width of the gap compared with the wavelength of the wave, the stronger the diffraction.
For example, when in Melbourne you may have noticed waves at St.Kilda, Elwood Beach, Williamstown, or Frankston. These waves have all passed through the narrow gap into Port Phillip from Bass strait. Diffraction of Different Types of Waves
Sound
Sound can diffract through a doorway or around buildings. Lower pitched sounds travel better than high-pitched sounds. This is because low-pitched sounds have a long wavelength compared with the width of the gap, so they spread out more.
Ultrasound
Ultrasound is sound with a high frequency. It has a very short wavelength compared with most gaps, so there is very little spreading. This makes sharp focusing of ultrasound easier, which is good for medical scanning.
Light
Light has a very short wavelength compared with most everyday gaps such as windows and doors. There is little obvious diffraction, so it produces sharp shadows.
Radio waves
Long wave radio signals are much less affected by buildings and tunnels than short wave radio signals or VHF radio signals. Because of diffraction, radio signals can sometimes be received in the shadow of hills.
Sound can diffract through a doorway or around buildings. Lower pitched sounds travel better than high-pitched sounds. This is because low-pitched sounds have a long wavelength compared with the width of the gap, so they spread out more.
Ultrasound
Ultrasound is sound with a high frequency. It has a very short wavelength compared with most gaps, so there is very little spreading. This makes sharp focusing of ultrasound easier, which is good for medical scanning.
Light
Light has a very short wavelength compared with most everyday gaps such as windows and doors. There is little obvious diffraction, so it produces sharp shadows.
Radio waves
Long wave radio signals are much less affected by buildings and tunnels than short wave radio signals or VHF radio signals. Because of diffraction, radio signals can sometimes be received in the shadow of hills.
REMEMBER - as well as behaving like a wave (reflecting, refracting diffracting and interfering) electromagnetic radiation also can act as a particle just like we saw in the spinning wheel demonstration where the light particles (or photons) were able to spin the wheel because they had momentum (and therefore mass.)
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