Technology Reference Libraries

Page 8 of about 94 Articles
Metal Detector
2010-10-06 21:55:14

A metal detector is a device that finds metal that may not be visible. The basic metal detector is composed of an oscillator producing an alternating current that passes through the coil producing an alternating magnetic field. If electrically conductive metal is close to the coil then the magnetic field is disrupted and thus the metal detector can sense the hidden metal. The first metal...

Safety Razor
2010-10-06 21:40:54

A safety razor, designed to protect the user from serious injury, is a razor where the facial skin is protected from all but the very edge of the blade. Prior to using a safety razor, most men used a straight razor. These razors, although still available today, are not used very often due to the skill and attention required for use. Jean-Jacques Perret invented the safety razor. A rare...

Roll Film
2010-10-06 21:28:02

Roll film is any type of spool-wound photographic film. The film is protected from white light exposure by a paper backing as opposed to film which is protected by being wound forward in a cartridge. It was originally referred to as "cartridge" film due to its resemblance to a shotgun cartridge. The film can be loaded in daylight since it has an opaque backing paper. During use, the spool of...

2010-10-04 16:28:51

The telephone is a telecommunications device that transmits and receives sound generally the human voice. The phone's basic function is to allow people who are separated by large distances to talk with each other. The telephone is used across the world and is one of the most common appliances in the developed world. The phone is designed to have a microphone, an ear piece which reproduces...

2010-10-04 16:15:56

Staplers, used widely in government, business, offices, and schools, are mechanical devices that join sheets of paper by driving a metal staple through the paper. The first stapler was created for King Louis XV. Each staple was inscribed with the insignia of royal court. George McGill created the predecessor of the modern staple. In 1867, he received a patent for a press to insert his...

Cathode Ray Tube
2010-10-04 16:07:17

The Cathode Ray Tube, which has internal or external means to accelerate and deflect electron beams, is a vacuum tube containing an electron gun and a fluorescent screen. The electron beams that are deflected are used to create images in the form of light emitted from the fluorescent screen. The CRT works by using an evacuated glass envelope which is large, deep, heavy, and relatively fragile....

2010-09-29 16:59:34

Dynamite, invented by Swedish chemist Alfred Nobel in 1867, is an explosive that harnesses the potential of nitroglycerin to explode. Normally it is sold in an 8 inch long stick and weighs about .6 pounds although other sizes do exist. TNT is usually the standard by which explosive power is gauged; however, dynamite actually has more than 60% greater energy density than TNT. Nitroglycerin...

Incandescent Light Bulb
2010-09-29 16:52:36

The incandescent light bulb provides a source of electric light through incandescence. The bulb works by passing current through a filament which heats to a temperature that produces light. The glass bulb that contains the filament prevents oxidation of the hot filament. The bulbs are also called electric lamps. Incandescent bulbs come in a various sizes and voltages. They can range from...

Mason Jar
2010-09-27 17:29:21

A Mason jar, invented by Rick Mason in 1858, is a glass jar used in canning to preserve food. Ball Corp. manufactured the jars early on and the name ball jar was also applied to the jars. In mass-production they have been replaced by other methods; however, in the home they are still widely used for canning. Usually the jars have a two piece lid composed of a inner flat metal which is...

Bunsen Burner
2010-09-27 17:09:09

A Bunsen burner produces a single open gas flame; it is commonly found in labs - used for heating, sterilization, and combustion. Robert Bunsen, in 1852, was hired at the University of Heidelberg and promised a new laboratory building. Heidelberg had just started installing coal-gas street lighting which provided light but not necessarily heat. Laboratory lamps, at the time, left much to be...

Word of the Day
  • A gift; a largess; a gratuity; a present; a dole.
The word 'donative' comes from a Latin word meaning 'to give'.