| A | B |
|---|
| light | a form of energy that is reflected from some objects |
| light ray | a straight-line beam of light as it travels outward from its source |
| law of reflection | the angle between an incoming light ray and a surface equals the angle between the reflected light ray and the surface |
| concave lens | a lens that is thicker at the edges than at the middle. As it curves inward, it spreads light rays apart, making images appear smaller |
| concave mirror | a mirror that curves in on the shiny side |
| convex lens | a lens that is thicker at the middle than at the edges. As it curves outward, it brings light together, making images appear larger |
| convex mirror | a mirror that curves out on the shiny side |
| reflection | the bouncing off or turning back of light from a surface |
| light source | the origin of light energy |
| bioluminescence | light produced by living organisms |
| shadow | a region of darkness where light is blocked |
| opaque | completely blocking light from passing through |
| transparent | letting all light through, so that objects on the other side can be seen clearly |
| translucent | lets some scattered light pass through but not all; will cast a light shadow |
| refraction | the bending of light rays as they pass from one substance into another |
| prism | a cut piece of clear glass (or plastic) with two opposite sides in the shape of a triangle or other geometric shape |
| spectrum | a band of colors produced when light goes through a prism |
| primary pigment | magenta, cyan, yellow; material with any of these colors absorbs one primary color of light and reflects the other two |
| electromagnetic spectrum | all the wavelengths of visible and invisible light in order from short (gamma rays) to long (radio) |
| laser | a device that produces a thin stream of light of just a few close wavelengths |
| visible spectrum | the portion of the electromagnetic spectrum that is visible to the human eye |
| optical illusion | an optical phenomenon that results in a false or deceptive visual impression |
