Tweezers
Encyclopedia
Tweezers are tools used for picking up and manipulating objects too small to be easily handled with the human
Human
Humans are the only living species in the Homo genus...

 hand
Hand
A hand is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs...

s. They are probably derived from tongs
Tongs
Tongs are used for gripping and lifting tools, of which there are many forms adapted to their specific use. Some are merely large pincers or nippers, but the greatest number fall into three classes:...

, pincer
Pincer (tool)
A pincer is a hand tool used in many situations where a mechanical advantage is required to pinch, cut or pull an object. Pincers are first-class levers, but differ from pliers in that the concentration of force is either to a point, or to an edge perpendicular to the length of the tool. This...

s, or scissors
Scissors
Scissors are hand-operated cutting instruments. They consist of a pair of metal blades pivoted so that the sharpened edges slide against each other when the handles opposite to the pivot are closed. Scissors are used for cutting various thin materials, such as paper, cardboard, metal foil, thin...

-like pliers
Pliers
Pliers are a hand tool used to hold objects firmly, for bending, or physical compression. Generally, pliers consist of a pair of metal first-class levers joined at a fulcrum positioned closer to one end of the levers, creating short jaws on one side of the fulcrum, and longer handles on the other...

 used to grab or hold hot objects since the dawn of recorded history. In a scientific or medical context they are normally referred to as forceps
Forceps
Forceps or forcipes are a handheld, hinged instrument used for grasping and holding objects. Forceps are used when fingers are too large to grasp small objects or when many objects need to be held at one time while the hands are used to perform a task. The term 'forceps' is used almost exclusively...

.

Tweezers make use of two third-class lever
Lever
In physics, a lever is a rigid object that is used with an appropriate fulcrum or pivot point to either multiply the mechanical force that can be applied to another object or resistance force , or multiply the distance and speed at which the opposite end of the rigid object travels.This leverage...

s connected at one fixed end (the fulcrum point of each lever), with the pincers at the others.

Tweezers can be used for tasks such as plucking human hairs
Plucking (hair removal)
Plucking or tweezing can mean the process of removing human hair, animal hair or a bird's feathers by mechanically pulling the item from the owner's body.In humans, this is done for personal grooming purposes, usually with tweezers...

 from the face or eyebrows, and whenever small objects have to be manipulated, including for example small, particularly surface-mount, electronic parts
Electronics
Electronics is the branch of science, engineering and technology that deals with electrical circuits involving active electrical components such as vacuum tubes, transistors, diodes and integrated circuits, and associated passive interconnection technologies...

, and small mechanical parts for model
Scale model
A scale model is a physical model, a representation or copy of an object that is larger or smaller than the actual size of the object, which seeks to maintain the relative proportions of the physical size of the original object. Very often the scale model is used as a guide to making the object in...

s and precision mechanisms. Stamp collectors
Stamp collecting
Stamp collecting is the collecting of postage stamps and related objects. It is one of the world's most popular hobbies, with the number of collectors in the United States alone estimated to be over 20 million.- Collecting :...

 use tweezers (stamp tongs
Stamp tongs
Stamp tongs are tweezers used to handle postage stamps. They are used by stamp collectors and philatelists, because they are a reliable way to hold and move stamps without damaging or getting skin oils on them. The jaws of stamp tongs are smooth in contrast to the striated jaws of the type of...

) to handle postage stamp
Postage stamp
A postage stamp is a small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage. Typically, stamps are made from special paper, with a national designation and denomination on the face, and a gum adhesive on the reverse side...

s which, while large enough to pick up by hand, could be damaged by handling; the jaws of stamp tongs are smooth. One example of a specialised use is picking out flake
Flake
Flake or Flakes may refer to:In food preparation:* Fish flake, a platform for drying cod* Flake , an Australian term for edible flesh of one of several species of shark...

s of gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...

 in gold panning
Gold panning
Gold panning, or simply panning, is a form of placer mining that extracts gold from a placer deposit using a pan. The process is one of the simplest ways to extract gold, and is popular with geology enthusiasts because of its cheap cost and the relatively simple and easy process involved. It is the...

.It also used in kitchens to remove bones from fillets of fish a process known as pin boning.

History

Tweezers are known to have been used in predynastic Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

. There are drawings of Egypt
Egypt
Egypt , officially the Arab Republic of Egypt, Arabic: , is a country mainly in North Africa, with the Sinai Peninsula forming a land bridge in Southwest Asia. Egypt is thus a transcontinental country, and a major power in Africa, the Mediterranean Basin, the Middle East and the Muslim world...

ian craftsmen holding hot pots over oven
Oven
An oven is a thermally insulated chamber used for the heating, baking or drying of a substance. It is most commonly used for cooking. Kilns, and furnaces are special-purpose ovens...

s with a double-bow shaped tool. Asiatic tweezers, consisting of two strips of metal brazed together, were commonly used in Mesopotamia and India from about 3000 B.C., perhaps for purposes such as catching lice. There is evidence of Roman shipbuilders pulling nails out of construction with plier-type pincers.

Types

Tweezers come in a variety of tip shapes and sizes. Blunt tip tweezers have a rounded end which can be used when a pointed object may get entangled, when manipulating cotton swabs, for example. Flat tip tweezers, pictured at right, have an angled tip which may be used for removing splinters. Some tweezers have a long needle-like tip which may be useful for reaching into small crevices. Triangular tip tweezers have larger, wider tips useful for gripping larger objects. Tweezers with curved tips also exist, sometimes called bent forceps
Forceps
Forceps or forcipes are a handheld, hinged instrument used for grasping and holding objects. Forceps are used when fingers are too large to grasp small objects or when many objects need to be held at one time while the hands are used to perform a task. The term 'forceps' is used almost exclusively...

. Microtweezers have an extremely small, pointed tip used for manipulating tiny electronic components and the like.

There are two common forms of construction for tweezers: two fused, angled pieces of metal, or one piece of metal bent in half. The latter is cheaper to manufacture, but gives weaker grip. The former is more expensive, but allows for a stronger grip. The width between the tips of the tweezers when no force is applied also affects how powerfully they grip.

The original tweezers for mechanical gripping have given rise to a number of tools with similar action or purpose but not dependent upon mechanical pressure, including
  • Optical tweezers
    Optical tweezers
    Optical tweezers are scientific instruments that use a highly focused laser beam to provide an attractive or repulsive force , depending on the refractive index mismatch to physically hold and move microscopic dielectric objects...

     use light to manipulate microscopic objects as small as a single atom
    Atom
    The atom is a basic unit of matter that consists of a dense central nucleus surrounded by a cloud of negatively charged electrons. The atomic nucleus contains a mix of positively charged protons and electrically neutral neutrons...

    . The radiation pressure from a focused laser beam is able to trap small particles. In the biological sciences, these instruments have been used to apply forces in the pico Newton range and to measure displacements in the nm range of objects ranging in size from 10 nm to over 100 mm.
  • Magnetic tweezers
    Magnetic tweezers
    A magnetic tweezer is a scientific instrument for exerting and measuring forces on magnetic particles using a magnetic field gradient. Typical applications are single-molecule micromanipulation, rheology of soft matter, and studies of force-regulated processes in living cells. Forces are typically...

     use magnetic forces to manipulate single molecules (such as DNA) via paramagnetic interactions. In practice it is an array of magnetic traps designed for manipulating individual biomolecules and measuring the ultra-small forces that affect their behavior.

  • Electric tweezers
    Electric tweezers
    Electric tweezers are an electronic device intended to permanently remove hair. The design incorporates a pair of tweezers at the tip. A button on the side of the handle is used to simultaneously close the tweezer tips and turn on the high frequency electrical signal...

     deliver an electrical signal through the tip, intended for depilation by damaging hair roots to prevent new hair from growing from the same root.
  • Vacuum tweezers use differences in atmospheric pressure to grasp items from 100 micrometres in size up to parts weighing several pounds. Special vacuum tweezer tips are manufactured to handle a wide variety of items such as surface-mount electronics, optics, biological material, stamps and coins. They may be used to handle parts that are so small that conventional mechanical tweezers may cause parts to be damaged or dropped and lost.
  • Molecular tweezers are noncyclic host molecules
    Host-guest chemistry
    In supramolecular chemistry, host-guest chemistry describes complexes that are composed of two or more molecules or ions that are held together in unique structural relationships by forces other than those of full covalent bonds. Host-guest chemistry encompasses the idea of molecular recognition...

     that have two arms capable of binding guests molecules through non-covalent bonding.
  • Hot, or soldering, tweezers combine the squeezing action of mechanical tweezers with heating, to grip small surface-mount electronic devices while simultaneously heating them, for soldering
    Soldering
    Soldering is a 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 workpiece...

     or desoldering.
  • Tweezer probes are a pair of electrical test probe
    Test probe
    A test probe is a physical device used to connect electronic test equipment to the device under test . They range from very simple, rugged devices to complex probes that are sophisticated, expensive, and fragile.- Voltage probes :Voltage probes are intended to measure voltages on the DUT...

    s fixed to a tweezer mechanism to measure voltages or other electronic circuit
    Electronic circuit
    An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...

     parameters between closely spaced pins.
  • Tweezers integrated with an electronic measuring device for evaluation of electrical parameters of small-size electronic components.

Other uses of the same principle are named tweezers; although such terms are not necessarily widely used their meaning is clear to people in the relevant field. E.g., Raman tweezers, which combine Raman spectroscopy
Raman spectroscopy
Raman spectroscopy is a spectroscopic technique used to study vibrational, rotational, and other low-frequency modes in a system.It relies on inelastic scattering, or Raman scattering, of monochromatic light, usually from a laser in the visible, near infrared, or near ultraviolet range...

with optical tweezers.
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