WAVE BEHAVIOR NOTES

Scattering

Scattering occurs when a wave bounces off an object in a variety of directions. The amount of scattering that takes place depends on the wavelength of the light and the size and structure of the object.

Diffraction

Waves can also bend to get around small barriers or to "squeeze through" small openings within a barrier. This is called diffraction. Diffraction is the bending and spreading of waves around an obstacle Waves can diffract if the obstacle is small or if the opening in the barrier is just wide enough to accommodate the wavelength of the wave. When light waves diffract, they produce a banding pattern.

Reflection

When a wave encounters a barrier, it can bounce off the surface of that barrier. This is called reflection. Reflection is a wave hits an object and bounces off. Reflection is the bouncing back of a wave when it meets a surface or boundary that does not absorb the entire wave's energy. All types of waves can be reflected. Waves tend to reflect best off flat/smooth, hard and/or shiny surfaces. Sound waves best reflect off hard surfaces such as brick walls or tile floors. The reflection of sound produces an echo. Light waves best reflect off calm water or mirrors. The reflection of light waves produces a mirror image. A mirror is a smooth and shiny surface that reflects light to produce clear images. A mirror's smooth surface causes light to reflect evenly off it. This is why mirrors can produce images.

Refraction

When a wave passes across a barrier into a new medium, such as from air into water, the wave bends. The bending of a wave is called refraction. Refraction is when waves change direction as they pass from one medium to another A wave refracts because its speed changes in the new medium. When speed of the wave changes, the direction of the wave changes and so it bends. Transmission Reflection A prism causes a unique type of light refraction. A prism is a transparent, triangular object that causes white light to separate into seven different colors. We call this dispersion. When white light enters a prism, the different colors refract differently. This causes white light to separate into a spectrum of colors.

Absorption

Absorption of a wave occurs when the energy of a wave is "soaked up" by the medium instead of being transferred through or reflected by the medium When a wave comes into contact with a medium and it causes the medium's molecules to vibrate and move. This vibration absorbs or takes the energy away from the wave One example of absorption is black pavement which absorbs energy from light. The black pavement becomes hot from absorbing the light waves.

Transmission

Transmission of waves occurs when waves pass through a given point or medium. Sound waves are transmitted through solids, liquids, and gases. Light waves are transmitted through transparent materials (may be clear or colored material such as filters) that allow most of the light that strikes them to pass through them. Only a small amount of light is reflected or absorbed. Opaque materials allow no light waves to be transmitted through them. Translucent materials transmit some light, but cause it to be scattered so no clear image is seen.