Laboratory Equipments Booklet

7/29/2019 Laboratory Equipments Booklet

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BEAKER

A beaker is a simple container for stirring, mixing andheating liquids commonly used in many laboratories.Beakers are generally cylindrical in shape, with a flat

bottom. Most also have a small spout (or "beak") to aidpouring as shown in the picture. Beakers are available in

A ring stand is used to provide support for other

equipment and a means of raising equipment above thework surface. Often times an iron bar screwed into aniron base makes up a ring stand; however, the holes you

see in the lab desk surface are receptacles for aluminum

rods that can be used in much the same manner as aring stand.

A utility clamp is used to provide stability andsupport for other equipment by attaching the equipmentto a ring stand

Ring Stand

Utility Clamp

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Gauze was originally made of silk and was usedfor clothing. It is now used for many different things, in-cluding gauze sponges for medical purposes. When usedas a medical dressing, gauze is generally made

of cotton. It is especially useful for dressing woundswhere other fabrics might stick to the burn or laceration.Many modern medical gauzes are covered with a plastic

porous film such as Telfa or a polyblend which preventsdirect contact and further minimizes wound adhesion.Also, it can be impregnated with a thick, creamy mixture

of zinc oxide and calamine to promote healing, asin Unna's boot.

Gauze

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a wide range of sizes, from one millilitre up to sever-al litres.

Structure

Standard or "Low-form" beakers typically have a height

about 1.4 times the diameter. The common low form

with a spout was devised by John Joseph Griffin and istherefore sometimes called a Griffin beaker. These are

the most universal character and are used for variouspurposes - from preparing solutions and decanting su-pernatant fluids to simple reactions.

Erlenmeyer flask

An Erlenmeyer flask, also known as a conicalflask, is a widely used type of laboratory flask which fea-tures a flat bottom, a conical body, and a cylindrical

neck.[1] It is named after the German chemist Emil Er-

lenmeyer, who created it in 1861.

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http://en.wikipedia.org/wiki/Silkhttp://en.wikipedia.org/wiki/Gauze_spongehttp://en.wikipedia.org/wiki/Dressing_(medical)http://en.wikipedia.org/wiki/Cottonhttp://en.wikipedia.org/w/index.php?title=Telfa&action=edit&redlink=1http://en.wikipedia.org/wiki/Zinc_oxidehttp://en.wikipedia.org/wiki/Calaminehttp://en.wikipedia.org/wiki/Unna%27s_boothttp://en.wikipedia.org/wiki/Unna%27s_boothttp://en.wikipedia.org/wiki/Calaminehttp://en.wikipedia.org/wiki/Zinc_oxidehttp://en.wikipedia.org/w/index.php?title=Telfa&action=edit&redlink=1http://en.wikipedia.org/wiki/Cottonhttp://en.wikipedia.org/wiki/Dressing_(medical)http://en.wikipedia.org/wiki/Gauze_spongehttp://en.wikipedia.org/wiki/Silk


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scale, is parallel to the beam, and connects the supportsof the two platforms. This rider is moved along the bar,

its edge marking decimal fractions of the unit weight.

Alcohol thermometer

The Alcohol thermometer or spirit thermometer isan alternative to the mercury-in-glass thermometer, andfunctions in a similar way. But unlike mercury-in-glass

thermometer, the contents of an alcohol thermometerare less toxic and will evaporate away fairly quickly.An organic liquid is contained in a glass bulb which is

connected to a capillary of the same glass and the end is

sealed with an expansion bulb. The space above the liq-uid is a mixture of nitrogen and the vapour of the liquid.

For the working temperature range, the meniscus or in-terface between the liquid is within the capillary. Withincreasing temperature, the volume of liquid expandsand the meniscus moves up the capillary. The position of

the meniscus shows the temperature against an in-scribed scale. It is an important need for science experi-ments.

T h e l i q u i d u s e d c a n b e

pure ethanol, toluene, kerosene or Isoamyl acetate, de-

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flasks used in cell culture are pre-sterilized and featureclosures and vented closures to enhance gas exchange

during incubation and shaking.

Petri dish

A Petri dish (or Petri plate or cell culture dish) is ashallow glass or plastic cylindrical lidded dishthat biologists use to culture cells or small mossplants. It was named after German bacteriologist Julius

Richard Petri, who invented it when working as an assis-tant to Robert Koch. Glass Petri dishes can be reusedby sterilization (for example, in an autoclave or by dry

heating in a hot air oven at 160 C for one hour). For ex-periments where cross-contamination from one experi-ment to the next can become a problem, plastic Petri

dishes are often used as disposables.

Modern Petri dishes often have rings on the lidsand bases, which allow them to be stacked so that they

do not slide off one another. Multiple dishes can also be

incorporated into one plastic container to create what is

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called a "multi-well plate". Petri dishes are usually usedto culture bacteria.

Microbiology

Petri dishes are often used to make agarplates for microbiology studies. The dish is partially filled

with warm liquid containing agar and a mixture of specif-i c i n g r e d i e n t s t h a t m a y i n -clude nutrients, blood, salts, carbohydrates, dyes, indi-

cators, amino acids and antibiotics. After the agar coolsand solidifies, the dish is ready to receive a microbe-laden sample in a process known as inoculation or

"plating." For virus or phage cultures, a two-step inocu-lation is needed: bacteria are grown first to providehosts for the viral inoculum.

Petri plates are incubated upside down (agar on

top) to lessen the risk of contamination from settling air-borne particles and to prevent water condensation fromaccumulating and disturbing the cultured microbes.

Scientists have long been growing cells in naturaland synthetic matrix environments to elicit phenotypesthat are not expressed on conventionally rigid sub-

strates. Unfortunately, growing cells either on or withinsoft matrices can be an expensive, labor intensive, andimpractical undertaking.

Other uses

Petri dishes are also used for eukaryotic cell cul-ture in liquid medium or using solid agar. Empty Petridishes may be used to observe plant germination or

small animal behavior, or for other day-to-day laborato-ry practices such as drying fluids in an oven and carryingand storing samples. Their optical transparency and flat

profile lend them to their common use as a temporary

receptacle for viewing samples (especially liquid ones)under a low power microscope.

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A traditional cylinder (A in the image) is usuallynarrow and high (so as to increase the accuracy of vol-

ume measurement) and has a plastic or glass stem anda "spout" for easy pouring from the measured liquid.

Certain types of cylinders (B in the picture) have groundglass joints instead of a "spout", so that they can beclosed with a stopper or connect directly with other ele-

ments of a manifold; they are also known as mixing cyl-inders.[1] With this kind of cylinder, the metered liquiddoes not pour directly, but is often removed using

a cannula. A graduated cylinder is meant to be readwith the surface of the liquid at eye level, where the cen-

ter of the meniscus shows the measurement line. Typi-cally the accuracy of the graduated cylinder is +/-0.05

mL. The measuring cylinder is normally and most com-monly used in laboratories or middle and high school sci-ence classes.

Plat form balance

The platform balance is a form of equal-arm bal-

ance in which two flat platforms are attached to the top

side of the beam, one at each end. Such a balance has arider, or weight, mounted on a bar that has a calibrated

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Graduated cylinder

A graduated cylinder, measuring cylin-der or graduate is a piece of laboratory equip-ment used to accurately measure the volume of a liquid.Water displacement can be used to find out the volumeof a solid. Graduated cylinders are generally more accu-r a t e a n d p r e c i s e f o r t h i s p u r p o s e

than flasks andbeakers. Often, the largest graduatedcylinders are made of polypropylene for its excellent

chemical resistance or polymethylpentene for its trans-parency, making them lighter and less fragile than glass.

Polypropylene is easy to repeatedly autoclave; howev-er, autoclaving in excess of about 130 C (266 F)(depending on the chemical formulation: typical com-

mercial grade polypropylene melts in excess of 160 C(320 F)),can warp or damage polypropylene graduat-ed cylinders, affecting accuracy.

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Alcohol lamps

Alcohol lamps are usually found in biology labswhere they do innoculations of bacteria cultures. It heatsthe wire loop on a stick that they use to spread the bac-

teria on the growth medium, which will prevent contami-nation to the cultures. They are more portable than Bun-sen burners but burn at a lower temperature. Note* I haven't seen these around in a long time, andwith the common use of disposable plastic innoculators,they might not be that common anymore.

Alcohol lamp-serves as a source of heat for labor-atory activity. For gently heating small to medium

amounts of materials. Glass lamp includes stopper, wick

and cap.

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Funnel

A funnel is a pipe with a wide, often conical mouth

and a narrow stem. It is used to channel liquid or fine-grained substances into containers with a small opening.

Without a funnel, spillage would occur.

Funnels are usually made of stainlesssteel, aluminium, glass, or plastic. The material used inits construction should be sturdy enough to withstandthe weight of the substance being transferred, and it

should not react with the substance. For this reason,stainless steel or glass are useful in transferringdiesel,while plastic funnels are useful in the kitchen. Some-times disposable paper funnels are used in cases whereit would be difficult to adequately clean the funnel after-ward (for example, in adding motor oil to a car). Dropper

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mark the scale. Also, the spring in the scale can perma-nently stretch with repeated use.

If two spring scales are hung one below the otherin series, each of the scales will read the weight of thebody hung on the lower scale. The scale on top would

read slightly heavier due to being stretched by the

weight of the lower scale.

Spring scales come in different sizes. Generally,

small scales that measure newtons will have a less firmspring (one with a smaller spring constant) than largerones that measure tens, hundreds or thousands of new-

tons.

Uses

Spring scales can be used in physics and educa-

tion as basic accelerometers, but its main uses are in-dustrial, especially related to weighing heavy loads suchas trucks,storage silos, and material carried ona conveyor belt. Spring scales are used when the accu-

racy afforded by other types of scales can be sacrificedfor simplicity, cheapness, and robustness. A spring bal-ance measures the weight of an object by opposing the

force of gravity with the force of an extended spring.

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Spring scale

The spring scale apparatus is simply a spring fixedat one end with a hook to attach an object at the other.

It works by Hooke's Law, which states that the forceneeded to extend a spring is proportional to the distancethat spring is extended from its rest position. Thereforethe scale markings on the spring scale are equally

spaced.

Spring scales can be calibrated for the accuratemeasurement of mass in the location in which they areused, but many spring scales are marked right on their

face "Not Legal for Trade" or words of similar import,due to the approximate nature of the theory used to

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funnels, also called dropping funnels or tap funnels, havea tap to allow the controlled release of a liquid.

The term funnel is sometimes used to refer tothe chimney or smokestack on a steam locomotive andusually used in referring to the same on a ship. There is

also a type of spider known as a funnel-web due to its

habit of building its web in the shape of a funnel. Theterm funnel is even applied to other seemingly strange

objects like a smoking pipe or even a humble kitch-en bin.

Laboratory funnels

There are many different kinds of funnels thathave been adapted for specialized applications in the la-

boratory. Filter funnels, thistle funnels (shaped

like thistle flowers), and dropping funnels have stop-cocks which allow the fluids to be added to a flask slow-ly. For solids, a powder funnel with a wide and shortstem is more appropriate as it does not clog easily.

When used with filter paper, filter fun-nels, Bchner and Hirsch funnels can be used to re-move fine particles from a liquid in a process

called filtration. For more demanding applications, thefilter paper in the latter two may be replaced with a sin-tered glass frit.

Construction

Glass is the material of choice for laboratory appli-cations due to its inertness compared with metals or

plastics. However, plastic funnels made of nonreac-

tive polyethylene are used for transferring aqueous so-lutions. Plastic is most often used for powder funnelsthat do not come into contact with solvent in normal

use.

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Test tube

A test tube, also known as a culture

tube or sample tube, is a common piece of laboratoryglassware consisting of a finger-like length of glass orclear plastic tubing, open at the top, usually with arounded U-shaped bottom.

Test tubes are available in a multitude of lengthsand widths, typically from 10 to 20 mm wide and 50 to200 mm long. The top often features a flared lip to aidpouring out the contents; some sources consider thatthe presence of a lip is what distinguishes a test tubefrom a culture tube. Some test tubes have a flat bottom;some are made so as to accept a ground glass stop-

per or a screw cap. They are often provided with asmall ground glass or white glaze area near the top forlabeling with a pencil.

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. Crucible

A crucible is a container that can withstand veryhigh temperatures and is used for metal, glass,and pigment production as well as a number of modernlaboratory processes. While crucibles historically were

usually made from clay,[1] they can be made from anymaterial that withstands temperatures high enough tomelt or otherwise alter its contents.

Typology and chronology

The form of the crucibles has varied through time,with designs reflecting the process for which they are

used, as well as regional variation.The crucible helps toprevent the heat from affecting the solution.

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Laboratory tripod is a three-legged equipment,generally used as a platform of some sort. The word is

derived from Greek word tripous, meaning "three feet".A tripod stand has three legs and is widely used in labor-ator ies to conduct var ious experiments.

This lab equipment is used to support and hold various

flasks, beakers and other glass ware when not in useand also during experiments. The stands are speciallyconstructed using light metals for light weight and easeof carrying. The height of Laboratory can also be adjust-

ed according to individual requirements.

These folding and portable units are suitable forlaboratories with less open space. Some tripod standshave a cast iron top with mild steel legs, bent outwards

for more stability.

Materials Used

This lab equipment is constructed using various

materials including:

Stainless Steel

Top of the equipment and concentric ringsare Chromium plated.

Aluminium

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Uses

Test tubes are widely used by chemists to hold,mix, or heat small quantities of solid or liquid chemicals,especially for qualitative experiments and assays. Theirround bottom and straight sides minimize mass losswhen pouring, make them easier to clean, and allow

convenient monitoring of the contents. The long, narrowneck slows down the spreading of vapors and gases to

the environment.

A test tube filled with water and upturned into awater-filled beaker is often used to capture gases, e.g.

in electrolysis demonstrations.

Stirring rod

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A stirring rod or stir rod is a piece of laboratoryequipment used to mix chemicals and liquids for labora-

tory purposes. They are usually made of solid glass,about the thickness and slightly longer than a drinkingstraw, with rounded ends. Like most laboratory glass,

stir rods are made of borosilicate (commonly known aspyrex).

Distilling Flask

Distilling flasks are made of glass, and consist of

three main parts: a spherical base, a cylindrical neck,and a cylindrical sidearm that is connected to the flask

neck. They are usually made of a type of glass (such asPyrex) that can withstand high temperatures.

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as acetone, isopropanol or ethanol. In biological labs it iscommon to keep sodium hypochlorite solution in a wash

bottle to conveniently disinfect unneeded cultures.

Iron Tongs

Tongs are used to hold many different things such

as flasks, crucibles, and evaporating dishes when theyare hot.

Tripod

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Wash bottle

A wash bottle is a squeeze bottle with a nozzle,used to rinse various pieces of laboratory glassware,such as test tubes and round bottom flasks.

Wash bottles are sealed with a screw-top lid.When hand pressure is applied to the bottle, the liquid

inside becomes pressurized and is forced out of the noz-zle into a narrow stream of liquid.

Most wash bottles are made up of polyethylene,which is a flexible solvent-resistant petroleum-basedplastic. Most bottles contain an internal dip tube allowing

upright use.

Wash bottles may be filled with a range of com-mon laboratory solvents and reagents, according to the

work carried out in that lab. These include:deionized wa-

ter, detergent solutions and rinse solvents such

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The distilling flask is used to separate liquid mix-tures by distillation. Distillation is the process of separat-

ing mixtures based on the difference in boiling points ofthe components of that mixture. As the flask and thecontents are heated, each component of the mixture

changes from the liquid phase to the gas phase(components change in order from lowest boiling point

to highest boiling point). As the molecules in the gasphase rise, they are usually routed through the sidearminto a condenser (the top of the neck is usually sealedwith a cork or rubber stopper).

Round-bottom flask

Round-bottom flasks (also called round-bottomedflasks and Erlenmeyer Bulbs) are types of flasks havingspherical bottoms used as laboratory glassware, mostly

for chemical or biochemical work. They are typically

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made of glass for chemical inertness; and in moderndays, they are usually made of heat-

resistant borosilicate glass. There is at least one tubularsection known as the neck with an opening at the tip.Two or three-necked flasks are common as well. Round

bottom flasks come in many sizes, from 5 mL to 5 L,with the sizes usually inscribed on the glass. In pilot

plants even larger flasks are encountered.

The ends of the necks are usually conical(female) ground glass joints. These are standardized,and can accept any similarly-sized tapered (male) fit-

tings. Standard Taper 24/40 is common for 250 mL orlarger flasks, while smaller sizes such as 14 or 19 areused for smaller flasks.

Because of the round bottom, cork rings are need-

ed to keep the round bottom flasks upright. When in

use, round-bottom flasks are commonly held at the neckby clamps on a stand.

Applications

The round bottoms on these types of flasks allowmore uniform heating and/or boiling of liquid. Thus,

round-bottom flasks are used in a variety of applicationswhere the contents are heated or boiled. Round-bottomflasks are usually used in distillation by chemists as dis-

tilling flasks and receiving flasks for the distillate (seedistillation diagram). One-neck round-bottom flasks areused as the distilling flasks in rotary evaporators.

This flask shape is also more resistant to fractur-

ing under vacuum, as a sphere more evenly distributesstress across its surface.

Round-bottom flasks are often used to con-

tain chemical reactions run by chemists, especiallyfor reflux set-ups and laboratory-scale synthesis. Boiling

chips are often added in distilling flasks for distillations

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principally methane) or a liquefied petroleum gas suchas propane, butane, or a mixture of both.

The hose barb is connected to a gas nozzle on thelaboratory bench with rubber tubing. Most laboratorybenches are equipped with multiple gas nozzles connect-

ed to a central gas source, as well as vacuum, nitrogen,

and steam nozzles. The gas then flows up through thebase through a small hole at the bottom of the barrel

and is directed upward. There are open slots in the sideof the tube bottom to admit air into the stream viathe venturi effect, and the gas burns at the top of the

tube once ignited by a flame or spark. The most com-mon methods of lighting the burner are using a match ora spark lighter.

The amount of air mixed with the gas stream af-

fects the completeness of the combustion reaction. Less

air yields an incomplete and thus cooler reaction, while agas stream well mixed with air provides oxygen in

an equimolar amount and thus a complete and hotterreaction. The air flow can be controlled by opening orclosing the slot openings at the base of the barrel, simi-

lar in function to the choke in acarburettor.

If the collar at the bottom of the tube is adjustedso more air can mix with the gas before combustion, the

flame will burn hotter, appearing blue as a result. If theholes are closed, the gas will only mix with ambient air

at the point of combustion, that is, only after it has exit-ed the tube at the top. This reduced mixing produces an

incomplete reaction, producing a cooler but brighter yel-low which is often called the "safety flame" or "luminousflame". The yellow flame is luminous due to

small soot particles in the flame which are heated toin-candescence. The yellow flame is considered "dirty" be-cause it leaves a layer of carbon on whatever it is heat-

ing. When the burner is regulated to produce a hot, blueflame it can be nearly invisible against some back-

grounds.

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Bunsen burner

A Bunsen burner, named after Robert Bunsen, is acommon piece of laboratory equipment that produces a

single open gas flame, which is used for heating, sterili-zation, and combustion.

Operation

Different flame types of Bunsen burner dependingon flow through the throat holes (holes on the side ofthe Bunsen burner -- not to be confused with the needle

valve for gas flow adjustment).1) air hole closed (Safetyflame used for when not in use or lighting).2) air holeslightly open.3) air hole half open.4) air hole almost fullyopen (this is the roaring blue flame).

The device in use today safely burns a continuousstream of a flammable gas such as natural gas (which is

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or boiling chemical reactions to allow a nucleation sitefor gradual boiling. This nucleation avoids a sudden boil-

ing surge where the contents may overflow from theboiling flask. Stirring bars or other stirring devices suitedfor round-bottom flasks are sometimes used. Round bot-

tom flasks suffer from poor stirring when comparedwith Erlenmeyer flasks, as they can't accept large stir

bars and material can become trapped at the base. For areflux set-up, a condenser is typically attached to themiddle or only neck of the flask being used. Additionalnecks on a flask could allow a thermometer or a me-

chanical stirrer to be inserted into the flask contents.The additional necks can also allow a dropping funnel tobe attached to let reactants slowly drip in.

Dropper

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A dropper is a simple instrument used in chemis-try to drop drops of chemicals. it is also a chemistry

measurement. if you needed two drops of iodine solution(eg) then you would squeeze the soft part of it and drop

one little drop into whateva you need to drop it on.

Test Tube Brushes

Test Tube Brushes - Stainless Steel - These brush-es have stainless steel wire stems and high grade nylonfor performance and durability.

Test Tube Brush - Tapered Radial End - TaperedRadial Tip brushes are designed to a have a slightly larg-er diameter at the tip of the brush, combined with a Ra-

dial tip ensuring that the brush makes complete contactwith round tube or bottle end for thorough cleaning.

Test Tube Brush - Sponge End - Sponge TipBrushes are designed to enter narrow mouthed bottles &

tubes and then expand to clean the sides of the bottle &tube, while protecting the bottom of the bottle or tubefrom being scratched by the wire tip.

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prepared as an aqueous solution that functions similar-ly. Under acidic conditions the solution is red, and under

basic conditions the solution is blue.

The litmus mixture has the CAS number 1393-92-6 and contains 10 to 15 different dyes. Most of the

chemical components of litmus are likely to be the same

as those of the related mixture known as orcein, but indifferent proportions. In contrast with orcein, the princi-pal constituent of litmus has average molecular weight of

3300.[2] Acid-base indicators on litmus owe their prop-e r t i e s t o a 7 -

hydroxyphenoxazone chromophore. Some fractions oflitmus were given specific names includ-

ing erythrolitmin (or erythrolein), azolitmin, spanio-litmin, leucoorcein and leucazolitmin. Azolitmin showsnearly the same effect as litmus.

Uses

The main use of litmus is to test whether a solu-tion is acidic or basic. Wet litmus paper can also be usedto test water-soluble gases; the gas dissolves in the wa-ter and the resulting solution colors the litmus paper. For

instance, ammonia gas, which is alkaline, colors the redlitmus paper blue.

Chemical reactions other than acid-base reactioncan also cause a color-change to litmus paper. For in-

stance, chlorine gas turns blue litmus paper white thelitmus paper is bleached[5], due to presence of hypo-chlorite ions. This reaction is irreversible and thereforethe litmus is not acting as an indicator in this situation.

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A medical aspirator is a small suction machineused to remove mucus and other bodily fluids from a patient. These machines are often designed to be porta-

ble for use in ambulances and nursing homes, and canrun on AC/DC or battery power. Major manufacturersinclude Allied Healthcare (under theGomco brand) andImpact. In the past manually operated aspirators were

used such asPotain's aspirator

Litmus Paper

Litmus is a water-soluble mixture of differ-

ent dyes extracted from lichens, especially Roccellatinctoria. It is often absorbed onto filter paper to pro-duce one of the oldest forms of pH indicator, used totest materials for acidity. Blue litmus paper

turns red under acidic conditions and red litmus paperturnsblue under basic (i.e. alkaline) conditions, with the

color change occurring over the pH range 4.5-8.3 at 25C. Neutral litmus paper is purple. Litmus can also be

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Test Tube Brushes - Radial Tip - These Test TubeBrushes are engineered to perform a wide variety of

cleaning functions. Radial Tip or Double Fan tip Brusheshave formed brush sprays at the tip of the brush. Thisallows the brush to thoroughly clean the bottom & cor-

ners of the bottle or tube, without scratching the glass-ware.

Test Tube Brush - Tied Tip - Tied Tip Brushes are

designed to enter narrow mouthed bottles & tubes andthen expand to clean the sides of the bottle & tube,while protecting the bottom of the bottle or tube from

being scratched by the wire tip.

Crucible Tongs

There are many utensils which have been made in

order to keep the food items in it and it becomes very

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important for the people to keep these utensils in theirhouse as in every house there are utensils. Wherever

there will be food the utensils will automatically be pre-sent in that particular place. Crucible Tongs are also ofthe same kind and they are made for special reasons

which are only fulfilled by these particular utensils whichhave been specially made for this particular reason.

It is not difficult to give a proper definition to this

particular thing as this is a proper utensil in which basi-cally that particular dish is put which is liquid in its form.This utensil is basically made to put a liquid dish because

it is deep in its structure and people find it very easy toput this liquid form dish in this because in this particularutensil the dish does not leak and it is properly put intoit.

Functions

The functions of these kinds of a thing are manyand it has been used specially to fulfil many purposes

which are said to be very important for the people. Inthe kitchen area now a days you will find that these kindof utensils are only used and the food products which

are made are generally put in this particular thing only.It is not necessary that these utensils are used in oneparticular region only but these utensils are used acrossthe world which is also a very important thing to look at.

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flows back into the solution. This does not happenin a dish.

When heating liquid in an evaporating dish, thelow walls encourage splashes and so stirring or swirlingof evaporating liquids is considered bad practice, owing

to the risk of spillage.

Evaporation in a laboratory, especially in produc-tion quantities rather than merely for analysis, is now

mostly performed in a rotary evaporator. This is pre-ferred because it works much faster and may be usedunder vacuum, avoiding unwanted reactions with the at-

mosphere and allowing control of noxious fumes. Evapo-ration under vacuum also reduces the severityof bumping and violent ebullition.

Aspirator

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exist)"[note 1], and sometimes to their melting point.

Evaporating dishes are used to evaporate excess sol-vents, most commonly water - to produce a concentrat-ed solution or a solid precipitate of the dissolved sub-stance.

Most are of porcelain or borosilicate glass. Shallow

glass evaporating dishes are commonly termed "watchglasses", from their original use as the front window ofa pocket watch.[note 2] Some used for high-temperature work are of refractory metals, usually

of platinum, owing to its non-reactive behaviour and lowrisk of contamination.

The capacity of evaporators is usually small - in

the range 3-10 ml. Larger dishes, up to 100 ml, are dif-ferent in shape, and are more hemispherical.

The evaporator is used most often in quantitativeanalysis.

In the determination of silicon content in an or-ganic sample, a small and accurately-measured quantityof a substance is added to the large amount ofsulfuric

acid, then heated in an evaporating dish. The dish isheated with a Bunsen burner, until only stable precipi-tate remains, which contains the silica content. The dish

is then closed and heated at high temperature until com-pletely clean, fused silica is produced. Comparison of the

initial weight of the substance and that of the fused silicaallows to the content of silicon in the sample to be deter-mined.

The shape of the evaporating dish encouragesevaporation in two ways:

The shell is relatively flat. A relatively large liquid sur-face promotes evaporation.

If heated in a flask or beaker, a part of the evapo-

rated liquid condenses on the vessel walls and

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Tweezers

Tweezersare tools used for picking up objects toosmall to be easily handled with the human hands. They

are probably derived from tongs, pincers, or scissors-like pliers used to grab or hold hot objects since thedawn of recorded history. In a scientific or medical con-

text they are normally referred to as forceps.

Tweezers make use of two third-

class levers connected at one fixed end (the fulcrumpoint of each lever), with the pincers at the others.

Tweezers can be used for tasks such as pluckinghair from the face or eyebrows, and whenever small ob-jects have to be manipulated, including for example

small, particularly surface-mount, electronic parts,and small mechanical parts formodels and precisionmechanisms. Stamp collectors use tweezers (stamptongs) to handle postage stamps which, while largeenough to pick up by hand, could be damaged by han-dling; the jaws of stamp tongs are smooth. One example

of a specialised use is picking out flakes of gold in goldpanning. It also used in kitchens to remove bones from

fillets of fish in a process known as19.

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Test Tube Holder

The holder is used to hold test tubes when theyare hot and untouchable.

Test tube rack

The test tube rack is used to hold test tubes while

reactions happen in them or while they are not needed.

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Design

Spatulas have a handle long enough to keep theholder's hand away from what is being lifted, or flipped.The blade often has one side longer than the other. Theright side (as used) tends to be longer than the left, asthis is more effective for right-handed people Left-

handed spatulas exist, but are rare. The blade may beperforated with holes or slots allowing liquids to flow

through.

Evaporating dish

An evaporating dish is a piece of laboratory glass-

ware used for the evaporation of solids and 23does not

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pestle is made of wood. This is known asa Wedgwood mortar and pestle and originated in 1779.

Today the act of mixing ingredients or reducing the par-ticle size is known astrituration. Mortars and pestles arealso used as drug paraphernalia to grind up pills to

speed up absorption when they are ingested, or in prep-aration for insufflation.

SpatulaThe term spatula is used to refer to various small

implements with a broad, flat, flexible blade used to mix,spread and lift materials including foods, drugs, plasterand paints. The term derives from the Latin word for a

flat piece of wood or splint (a diminutive form of the Lat-in spatha, meaning broadsword), and hence can also re-

fer to a tongue depressor. The words spade (diggingtool) and spathe are similarly derived. The word spatulais known to have been used in English since 1525.

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Mortar and pestleA mortar and pestle is a tool used to crush, grind,

and mix solid substances (trituration). The pestle is aheavy club-shaped object, the end of which is used forcrushing and grinding. The mortar is a bowl, typically

made of hard wood, ceramic or stone. The substance tobe ground is placed in the mortar and ground, crushedor mixed with the pestle. Sometimes referred to as an

"Apothecary Grinder" by individuals unfamiliar with its

use, the proper historical name is "mortar and pestle".

Medical use

Mortars and pestles were traditionally used

in pharmacies to crush various ingredients prior to pre-paring an extemporaneous prescription. The mortar andpestle, along with the Rod of Asclepius, the Green Cross,

and others, is one of the most pervasive symbols ofpharmacology,[3] along with the show globe. For phar-maceutical use, the mortar and the head of the pestle

are usually made of porcelain, while the handle of the

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Laboratory Equipments Booklet

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Transcript of Laboratory Equipments Booklet