Behavior of Light affects what we seeVisible light can travel through the vacuum of space and it can also travel through a medium.

There are three forms of interaction that affect how we see light – reflection, transmission, and absorption.

Reflection:Reflection is the bouncing back of a

wave after it strikes a barrier.Law of reflection: the angle of

reflection equals the angle of incidence.* If the angle of light hitting a surface comes in at 600 (angle of incidence), then the reflection of that light bouncing off of the surface is also 600 (angle of reflection).

Law of reflection

An example of the law of reflection: angle of incidence and angle of reflection are the same.

Regular reflection:Regular reflection is reflection of parallel light

rays all in the same direction.Examples of this type of reflection are –

mirrors, smooth pond surface, smooth metal surfaces, etc.

Regular reflection occurs on surfaces that are smooth.

Diffuse reflection:Diffuse reflection occurs when the reflection

of parallel light rays are in many different directions.

Any surface that is not truly smooth will cause diffuse reflection.

Transmission:Transmission is the passage of an EM wave

through a medium.There are two types of materials that allow the

transmission of light – transparent and translucent.

Transparent materials are materials that allow most of the light that strikes them to pass through. (air, water, clear glass)

Translucent materials are materials that transmit some light, but they also cause it to spread out in all directions. ( lampshades, frosted glass, sheer fabrics, notepaper)

And yet another type of material…Opaque materials are materials that do not

allow any light to pass through them, because they reflect light, absorb light, or both.

Opaque materials that reflect light – mirrors and other shiny materials.

Opaque materials that absorb light – wood, rocks, heavy fabrics.

Opaque materials that do both – ceramic mugs

Transparent versus Translucent

Opaque materials: