An X-ray machine is a device that produces X-rays and records the shadow they cast, which lets people see inside an object or a body without cutting it open. The rays were discovered in 1895 by the German physicist Wilhelm Conrad Röntgen, and medical imaging became their best-known use. The sources reviewed for this entry
A device that produces X-rays and records the shadow they cast, used most often in medicine to image the inside of the body.
A zipper is a fastener made of two rows of interlocking teeth carried on fabric tapes, joined or separated by a slide that moves along them. It closes clothing, bags, boots and many other products. Its development took decades and passed through several inventors, and Gideon Sundback’s patent of 1917 describes the design still used
A zipper is a fastener of interlocking teeth joined by a slide, with Gideon Sundback's 1917 patent describing the design still used.