The lighting parameters control how a light ray interacts with an object. These parameters give a surface its properties making it look like shiny metal or dull plastic.
Ambient light is specified as a percentage of the objects color.
Diffuse Diffuse light depends on the angle between the light source and the observer. Thus with a white light source the diffuse component will have the same color as the object. This parameter gives an object its shape. This parameter is specified as a percentage from 0-100. Specular Specular light is the reflection of the light source off of the object.