What is Diffraction?



Diffraction is the spreading of waves around obstacles or squeezing through a small hole. It occurs with sound waves, light, atoms, and subatomic particles.

Here is an example of diffraction around an object

This image was made by magnetizing a screwdriver and hanging ball bearing on it. A laser beam was then shined on the ball and the light was diffracted, or bent, around the ball. This is the image you see.

Here is an example of diffraction through a small hole

This is an image of a laser beam that was shined on a pie plate, which had a pinhole in the center. The light squeezed through the pinhole and was diffracted. This produced rings of light on the wall. The rings of light are due to constructive and destructive interference. This is produced when light waves that are in phase undergo contructive interference, and waves that are out of phase undergo destructive interference. The area where destructive interference occurs are the regions that are black, where as the red regions are examples of contructive interference.