Convex and concave lenses can both be used to correct defects of vision. The most commonly occurring defects of vision are ‘short sightedness’ and ‘long sightedness’. People who are ‘short sighted’ ...

Source: NOVA: "Galileo's Battle for the Heavens" This resource was adapted from NOVA: "Galileo's Battle for the Heavens." As early as the 1300s, eyeglasses made from convex, or outward-curving, lenses ...

When light moves from air into glass or plastic it is refracted close refractionProcess by which a wave changes speed and sometimes direction upon entering a denser or less dense medium, eg a light ...

Sir Isaac Newton once wrote, in what must be one of the most oft-quoted lines in the history of science, "If I have seen further it is by standing upon the shoulders of giants." Well, any of us who ...