Light and Optical Systems Vocabulary

A form of energy that helps us see. It can travel in a straight line, be reflected, and bend.

299, 798 km/s. The first reasonable measurement was made by Ole Romer in 1676, then a more accurate number, 299 798 km/s, was made by Albert A. Michelson in the 1920s.

Any device that uses light; for example, mirrors, lenses, microscopes, and telescopes

Optical device for viewing distant objects; there are two types: reflecting and refracting telescopes

Used a simple microscope of his own design to look at things like pond water and blood. He wrote about "little animalcules", which were actually very small organisms such as bacteria, algae, and red blood cells.

Telescope that uses two lenses to form an enlarged image

Telescope that uses a curved mirror and a lens to form an enlarged image

Device for viewing distant objects; made up of two short refracting telescopes fitted together

Diagram used to represent how light travels; each ray has an arrow to show the direction of travel

Describes materials that allow light to pass through with little or no reflection; for example, glass