Behavior of Waves

Interactions of Light When a wave strikes a new medium, it can be reflected, refracted, diffracted, polarized, or scattered. Reflection. Occurs when a wave bounces off a surface it can’t pass through. Does not change the speed or frequency of the wave, but it can be flipped upside down.

Refraction Bending of a wave as it passes at an angle from one medium into another. Occurs because one side of the wave slows down compared to the other.

Diffraction Bending of a wave as it travels around an object or through a barrier. The amount the wave diffracts depends on its wavelength. Large wavelength + small opening = large diffraction. Small wavelength + large opening = small diffraction.

Polarization Light travels out in all directions from a source. Polarized light only travels in ONE direction (plane). Unpolarized light can be turned into polarized light using a polarizing filter. A polarizing filter blocks waves in certain directions and makes the light travel in just one direction. Light reflecting from a nonmetallic flat surface, like a window or the surface of a lake, can become polarized. When the light hits a horizontal surface it reflects the horizontal waves more than the rest of the waves, causing a glare. Polarized sunglasses have vertically polarized filters to block the horizontally polarized light.

Scattering Scattering means that light is redirected as it passes through a medium. Small particles in the air scatter the short wavelength waves much more than long wavelengths, so to us the sky appears blue, even though air is colorless. Sunsets appear orange and red because as the sun sets, there is more atmosphere for the light to pass through which causes more scattering. The longer wavelengths of yellow, green, blue, and violet are scattered most, leaving only red and orange.