beam- A ray of light.  A laser produces a narrow beam of light.

color-  An observable characteristic produced by light rays with different wavelengths.  The seven colors seen in the spectrum are:  red, orange, yellow,  green, blue, indigo, and violet.

heat-  The state of being hot.    The sun gives off both light and heat, as do various manufactured objects, such as lamps and burning candles.

illuminate- To light up something.  It is easier to see an object when it is illuminated.

light- Form of electromagnetic radiation that can be detected by the eye.  Light allows human beings to see.

natural-  Produced by nature, not by people.  The sun is a natural source of light, as stars and fires.

opaque-  Having the property of stopping light from passing through. An opaque object casts a shadow.  The human body, steel, rock, concrete, and cardboard are all opaque materials.

prism-  An object that bends light and separates it into the colors of the spectrum.  A jar of water and a mirror can act as a prism, as can raindrops.

rainbow-  A phenomenon that appears in the sky when sunlight is reflected and refracted by countless drops of water in the sky.  Each drop of water acts like a prism, breaking the sunlight into the colors of the spectrum:  red, orange, yellow, green blue, indigo, and violet.

shadow-  An object that produces light.  The sun is a natural light source.  Flashlights, lamps, and streetlights are sources of light made by people.

spectrum-  The colors that make up white light.  These colors are found in a rainbow.

straight-  Not curved or wavy.  A ray of light travels in a straight line.

translucent-  Having the property of allowing some light to pass through, although some of the light that strikes is scattered.  Some examples of translucent objects are frosted glass, thin cloth, and paper.

transparent-  Having the property of allowing light to pass through.  Clear water and glass are transparent.