Information: - Soldering (AmE: , BrE: ), is a process in which two or more items (usually metal) are joined together by melting and putting a filler metal (solder) into the joint, the filler metal having a lower melting point than the adjoining metal. Soldering differs from welding in that soldering does not involve melting the work pieces. In brazing, the filler metal melts at a higher temperature, but the work piece metal does not melt. In the past, nearly all solders contained lead, but environmental and health concerns have increasingly dictated use of lead-free alloys for electronics and plumbing purposes. - An alloy is a mixture of metals or a mixture of a metal and another element. Alloys are defined by a metallic bonding character. An alloy may be a solid solution of metal elements (a single phase) or a mixture of metallic phases (two or more solutions). Intermetallic compounds are alloys with a defined stoichiometry and crystal structure. Zintl phases are also sometimes considered alloys depending on bond types (see also: Van Arkel-Ketelaar triangle for information on classifying bonding in binary compounds). - A magnifying glass (called a hand lens in laboratory contexts) is a convex lens that is used to produce a magnified image of an object. The lens is usually mounted in a frame with a handle (see image). - Lead, from the Old English "lead", is a chemical element with atomic number82 and symbolPb (after the Latin, "plumbum"). It has the second highest atomic number of all practically stable elements. As such, lead is located at the end of some decay chains of heavier elements, which in part accounts for its relative abundance: its stability exceeds those of other similarly-numbered elements. Lead is a soft, malleable, and heavy metal. Freshly cut lead has a bluish-white color that soon tarnishes to a dull grayish color when exposed to air; as a liquid, it has a shiny chrome-silver luster. Lead's density of 11.34g/cm exceeds those of most common materials. - Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing fusion, which is distinct from lower temperature metal-joining techniques such as brazing and soldering, which do not melt the base metal. In addition to melting the base metal, a filler material is typically added to the joint to form a pool of molten material (the weld pool) that cools to form a joint that is usually stronger than the base material. Pressure may also be used in conjunction with heat, or by itself, to produce a weld. - A helping hand , also known as a third hand or X-tra Hands , is a type of extremely adjustable jig used in soldering and craftwork to hold materials near each other so that the user can work on them . A commonly produced version consists of a weighted base , a pair of twice - adjustable arms ending in crocodile clips , and optionally a magnifying glass , held together by flexible joints . The clips are used to hold a light workpiece in place while the joints allow the user to change the position or angle . Sometimes helping hands are augmented with modules from the adjustable coolant hose systems used with machine tools . - A filler metal is a metal added in the making of a joint through welding, brazing, or soldering. - Solder (or in North America ) is a fusible metal alloy used to create a permanent bond between metal workpieces. The word solder comes from the Middle English word "soudur", via Old French "solduree" and "soulder", from the Latin "solidare", meaning "to make solid". In fact, solder must be melted in order to adhere to and connect the pieces together, so a suitable alloy for use as solder will have a lower melting point than the pieces it is intended to join. Whenever possible, the solder should also be resistant to oxidative and corrosive effects that would degrade the joint over time. Solders intended for use in making electrical connections between electronic components also usually have favorable electrical characteristics. - A crocodile clip (also alligator clip or spring clip) is a sprung metal clip with long, serrated jaws which is used for creating a temporary electrical connection. This simple mechanical device gets its name from the resemblance of its jaws to that of an alligator's or crocodile's. It is used to connect an electrical cable to a battery or some other component. Functioning much like a spring-loaded clothespin, the clip's tapered, serrated jaws are forced together by a spring to grip an object. When manufactured for electronics testing and evaluation, one jaw of the clip is typically permanently crimped or soldered to a wire, or is bent to form the inner tubular contact of a ~4mm female banana jack, enabling quick non-permanent connection between a circuit under test and laboratory equipment or to another electrical circuit. The clip is typically covered by a plastic shroud or "boot" to prevent accidental short-circuits. - The melting point (or, rarely, liquefaction point) of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends on pressure and is usually specified at standard pressure. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point or crystallization point. Because of the ability of some substances to supercool, the freezing point is not considered as a characteristic property of a substance. When the "characteristic freezing point" of a substance is determined, in fact the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice", that is, the melting point. - Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the adjoining metal. - IMAGE (from Imager for Magnetopause-to-Aurora Global Exploration), or Explorer 78, was a NASA MIDEX mission that studied the global response of the Earth's magnetosphere to changes in the solar wind. It was launched March 25, 2000 by a Delta II rocket from Vandenberg AFB and ceased operations in December 2005. - Plumbing is any system that conveys fluids for a wide range of applications. Heating and cooling, waste removal, and potable water delivery are among the most common uses for plumbing; however, plumbing is not limited to these applications. Plumbing utilizes pipes, valves, plumbing fixtures, tanks, and other apparatuses to convey fluids. In the developed world plumbing infrastructure is critical for public health and sanitation. After reading the paragraphs above, we are interested in knowing the entity with which 'helping hand ' exhibits the relationship of 'subclass of'. Find the answer from the choices below. Choices: - ability - alloy - base - character - chemical element - color - delta - density - device - electronics - english - fusion - glass - heat - heating - image - information - infrastructure - intermetallic - laboratory - latin - lead - liquid - material - metal - mission - mixture - number - old english - order - phase - point - pressure - process - property - range - second - single - soldering - solution - stability - state - structure - system - temperature - van - via - welding - white - work
The answer to this question is:
device