A funnel is a tube or pipe that is wide at the top and narrow at the bottom, used for guiding liquid or powder into a small opening. Funnels are usually made of

stainless steel Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...

, aluminium, glass, or plastic. The material used in its construction should be sturdy enough to withstand the weight of the substance being transferred, and it should not react with the substance. For this reason, stainless steel or glass are useful in transferring

diesel Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engin ...

, while plastic funnels are useful in the kitchen. Sometimes disposable paper funnels are used in cases where it would be difficult to adequately clean the funnel afterwards (for example, in adding

motor oil Motor oil, engine oil, or engine lubricant is any one of various substances used for the lubrication of internal combustion engines. They typically consist of base oils enhanced with various additives, particularly antiwear additives, deterg ...

into a car). Dropper funnels, also called

dropping funnels Drop, DROP, drops or DROPS may refer to: * Drop (liquid) or droplet, a small volume of liquid ** Eye drops, saline (sometimes mydriatic) drops used as medication for the eyes * Drop (unit), a unit of measure of volume * Falling (physics), allowin ...

or tap funnels, have a tap to allow the controlled release of a liquid. A flat funnel, made of polypropylene, utilises

living hinge A living hinge or integral hinge is a thin flexible hinge (flexure bearing) made from the same material as the two rigid pieces it connects. It is typically thinned or cut to allow the rigid pieces to bend along the line of the hinge. The m ...

s and flexible walls to fold flat. The term "funnel" may refer to the chimney or smokestack on a steam

locomotive A locomotive or engine is a rail transport vehicle that provides the Power (physics), motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, Motor coach (rail), motor ...

and commonly refers to the same on a ship. The term ''funnel'' is also applied to other seemingly strange objects like a

smoking pipe A smoking pipe is used to inhale the smoke of a burning substance; most common is a tobacco pipe, which can also accommodate almost any other substance. Pipes are commonly made from briar, heather, corn, meerschaum, clay, cherry, glass, porcela ...

or a kitchen bin.

Laboratory funnels

There are many different kinds of funnels that have been adapted for specialised applications in the laboratory.

Filter funnel A filter funnel is a laboratory funnel used for separating solids from liquids via the laboratory process of filtering. In order to achieve this, a cone-like shaped piece of filter paper is usually folded into a cone and placed within the funnel. ...

thistle funnel A thistle tube is a piece of laboratory glassware consisting of a shaft of tube, with a reservoir and funnel-like section at the top. Thistle tubes are typically used by chemists to add liquid to an existing system or apparatus. Thistle funnels a ...

s (shaped like thistle flowers), and dropping funnels have stopcocks which allow the fluids to be added to a flask slowly. For solids, a powder funnel with a wide and short stem is more appropriate as it does not clog easily. When used with filter paper, filter funnels,

Büchner Büchner (or Buechner) is a German language surname related to the word ''Buche'' (german: beech) and may refer to: * Eberhard Büchner (born 1939), German tenor * Ernst Büchner (1850–1925), German chemist after whom the Büchner flask and Büc ...

and

Hirsch funnel Hirsch may refer to: Places * Hirsch, Saskatchewan, Canada * Hirsch Observatory, in Troy, New York, U.S. People * Afua Hirsch (born 1981), Norwegian-born British writer, broadcaster, and former barrister * Alex Hirsch (born 1985), American anim ...

s can be used to remove fine particles from a liquid in a process called filtration. For more demanding applications, the filter paper in the latter two may be replaced with a sintered glass frit. Separatory funnels are used in liquid-liquid extractions. The Tullgren funnel is used to collect arthropods from plant litter or similar material.

Construction

Glass is the material of choice for laboratory applications due to its inertness compared with metals or plastics. However, plastic funnels made of nonreactive polyethylene are used for transferring aqueous solutions. Plastic is most often used for powder funnels that do not come into contact with solvent in normal use.

Uses

* To channel liquids or fine-grained substances into containers with a small opening. Used for pouring liquids or powder through a small opening and for holding the filter paper in filtration. Used in transferring liquids in small containers. * Funnels known as killing cones are used to slaughter individual birds in poultry farming. The funnel is used to hold a bird upside down so that it can be bled more easily.SPARREY, J., SANDERCOCK, D., SPARKS, N., & SANDILANDS, V. (2014). Current and novel methods for killing poultry individually on-farm. ''World's Poultry Science Journal,'' ''70''(4), 737-758. doi:10.1017/S0043933914000816

Culture

Hieronymus Bosch-Removing the Rocks from the Head-Detail

The inverted funnel is a symbol of madness. It appears in many Medieval depictions of the mad; for example, in Hieronymus Bosch's ''Ship of Fools (painting), Ship of Fools'' and ''Allegory of Gluttony and Lust''. In popular culture, the Tin Woodman in L. Frank Baum's novel ''The Wonderful Wizard of Oz'' (and in most dramatizations of it) uses an inverted funnel for a hat, though that is never specifically mentioned in the story—it originated in W. W. Denslow's original illustrations for the book. In the East Coast of the United States, "beer funnel" is another term for "beer bong". "Funneling" a beer involves pouring an entire beer into a funnel attached to a tube, in which a person then consumes the beer via the tube. In the computing world, a funnel is frequently used as the icon for the Filter (software), filter functionality.

References

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