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Pyrex and Bomex: The glass your labware is made of.

When it comes to labware, there is only one material to use: Pyrex… no wait that’s not right, that’s a brand name. beaker

The actual answer is Borosilicate glass.

Borosilicate glass has a lot of brand names: Pyrex is the most well known (a product of Dow Corning) but as the material itself is not subject to copyright there are more than a few other names: Bomex, Pallex, and a few others. But in the end they are all Borosilicate glass, from the lowliest test tube to the fanciest distillation equipment.

Why Borosilicate glass? The answer is that borosilicate glass is very resitant to heat. Its not that it doesn’t get hot when heated, but rather when heated it does not expand like other types of glass. If another type of glass was used the expansion from heating would result in the labware shattering.

This is not to say that borosilicate glass is not immune to the effects of flame. In fact you really should not expose glass labware to direct flame if you can avoid it.  Use a hot plate, or seperate the flame from the glass with a ceramic pad.

Borosilcate glass is highly valued for its lack of expansion when heating – in fact higher-end reflecting telescopes make the mirrors out of borosilicate glass because the low expansion means the sensitive surface of the mirror will not change as the telescope goes from a warm indoors to a cold winter’s night.

So why do they make labware out of glass at all? Why not some other material? Well the main reason is visbility – when doing labwork you need to see what is happening in the glassware wether you need to see it to measure it or to observe the reaction taking place. The secondary answers are; metal won’t react well with acids, cermics need to be too thick to heat quickly, plastic doesn’t heat well, scratches, and is bad with some checmicals (not that they don’t make plastic labware).

So back to the glass – some often ask us if it matters if the glass is made of the brand Pyrex or not. the answer is: it depends, but probably not.

You see, all glass labware might be made of the same glass (branded or not) but not all glass labware is constructed the same. A 500ml beaker from a cheap brand might have thinner glass than a ‘name’ brand. Other factors that enter labware prices are: calibration (how much effort did they spend make sure the markings are accurate), labelling (do the markings stay on the glassware? not always!) design (some labware may not have a rolled top to preventing chipping or lack a pouring spout in certain beakers) all labware is a compromise of features vs. price somewhere. But whatever they do with the design, they will be using borosilicate glass.

Want to buy labware?

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10 Fun Facts About Labware

Labware? Is that a topic you can have a ‘Fun Fact list about? Well, let’s find out!

1) Most glass Labware is made from Borosilicate Glass. It is used because it has low thermal expansion properties. What this means is when you heat up the glass it won’t expand and thus shatter like regular glass would. A brand name for Borosilicate glass that most people are familiar with is Pyrex, which is used in many kitchenware products that needs to put up with the heat.

2) A beaker has straight sides, a flask can have angled or even curved sides. 661

3) While most labware is made of glass, a not insignificant quantity is made of plastic. This is handy for experiments where no heating is needed and the threat from dropping glass labware is a real danger.

4) The vast majority of glassware is considered ‘Class B’ glassware. Which is good for most measurements. ‘Class A’ labware is much more expensive and is much more accurately calibrated for measuring. It isn’t necessarily better made.

5) Yes, Virginia, there really are 10L Griffin Beakers!

BigGriffin

6) Griffin Beakers are named after 19th Century Jon Joseph Griffin, Erlenmeyer Flasks are named after 19th-20th century German chemist Emil Erlenmeyer. They are among the very few types of labware named after people. Most other labware is more descriptive of its shape or task: Measuring Cylinder, Round-Bottom Flask, Pipettor, etc.

7) What should type of labware should you use? Depends on what you are doing. Simple reactions should use a Griffin beaker, shaking something up? Use an Erlenmeyer Flaks. Need precise even heating of a mixture? Use a Round Bottom Flask (and support), filtering something? its easier to filter to a smaller mouthed flask than a beaker, etc, etc.

8) Far and away the most popular labware are simple Test Tubes. They are used for a variety of purposes such as mixing, heating, etc. Test tubes have to do these things on a small scale, however.

9) Many reactions done in flasks need a stopper of some kind to keep the liquids in the flask. Be careful when buying a stopper however as most measurements are done for rubber stoppers. Cork stoppers use an entirely different scale!

10) Cleaning labware is one of the most critically underrated needs of a laboratory. Most flasks won’t get clean in a dishwasher, for example as they have such small mouths the water won’t get in, pipette tubes are too small and long for the water to get in, etc.  Washing by hand is usually what is required in most cases. To help out labware producers and sellers often have an entire line of specialty bottle brushes to help with the cleaning. Pass the soap!

Want to buy labware or other Lab Equipment?

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New, Affordable Organic Chemistry Labware Sets.

Organic Chemistry lab sets have been around for a while. They are excellent sets for making limited quantities of various organic compounds.  Sets like our Macroscale Glass Chemistry Set are excellent for classroom and basic production. But these aren’t cheap. Although these sets are a bargain compared to some of the big labware producer’s sets, they are still a bit high for many folks trying to get equipment for the classroom.

Now a couple of sets are available that are much more affordable, the 9 piece Organic Chemistry Set and the Deluxe 16 piece Organic Chemistry Set, both from our regular glassware supplier United.

These kits, along with some basic lab equipment like stands and burners will allow students and experimenters to make small quantities of compounds. The essentials are covered with the 9 piece kit being suitable for preparations of up to 30g and the deluxe being suitable for preparations of up to 150g.

Both kits come in a sturdy, form-fitting case.

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Laboratory Glassware – A Primer, Part 2

Continued from Laboratory Glassware – Part 1

There are a few more flask designs to cover:

Round Bottom Flasks

Round bottom flasks are most often used for heating or chemical reactions. Their curved bottoms mean that there are no corners for materials to get stuck in,  nor hot spots or weak points to form. Round bottom flasks are often part of systems and so while many have 1 neck, others designs may have 2 necks or 3 necks! These necks often have glass joints for joining to adapters and tubes.

Since they are used for heating or must join with other glass lab systems round bottom flasks are almost exclusively made of borosilicate glass.  The big disadvantage of round bottom flasks is that they can’t stand up on a table on their own.  They require a lab system to support them or use of a flask stand.

Flat Bottom Flasks

Flat bottom flasks are round flasks, usually 1-neck, that are used for heating in distillation or other reagent reactions. They are not as durable as round bottom flasks but don’t have the sharp and vulnerable corners of an Erlenmeyer Flask.Their flat bottoms do allow them to stand up on a hot plate, shelf, or table.

Volumetric Flasks

Volumetric flasks are use to make compounds to a decent degree of accuracy (the accuracy depends on Class ‘A’ or ‘B’ quality). To ‘operate’ a volumetric flask you put the correct mass of a compound (powder, concentrated liquid, etc)  required to make a 1 molar, 2 molar, etc. mixture and then add water to the line marked on the long neck.  The long neck and stopper (every Volumetric flask should come with some kind of stopper) allow for vigorous shaking to make the mixture. Volumetric flasks can be made of glass or plastic since they are not used for reactions or heating. Plastic is less expensive but more prone to staining, and it is also not as accurate.

Filtration Flasks

Filtration Flasks are Erlenmeyer flasks with a spout for attaching a hose. That

Filtration Flask

hose runs to a vacuum pump that pulls the air out of the flask. When this happens a special funnel system (sometimes just filter paper) sitting on top of the flask. The pump pulls the liquid and smaller particles through the paper and into the flask. The larger particles get left behind on the filter. Filtering flasks need a lot of strength so they are built out of glass and have much thicker walls than their regular Erlenmeyer flask counterparts.

 

Continued in Part 3

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Laboratory Glassware – A Primer Part 1

There are dozens and dozens of different types of lab glassware available to anyone who wants to buy them. But all of these different types of glassware can get rather confusing to folks so we figured is was time for a little educational post about the many different kinds of glassware than scientists use:

We’ll start with the basics.

Griffin Beakers: These are one of themost common pieces of glassware out there. They are pretty much just glasses with graduations to show much they are holding (usually in ml). They should be made of borosilicate glass (which has many brand names: Pyrex, Bomex, etc). and can go in size from 5ml up to 10,000ml. They usually have a pouring spout and are capable of holding liquids or powders. Griffin beakers are used for mixing or heating chemicals or for staging chemical reactions.

Plastic versions of Griffin Beakers are available where breakage might be a concern, but plastic is completely unsuited to some chemical reactions and cannot be used for heating.

Erlenmeyer Flasks:

A flask is different from a beaker in that it has sloping or round sides rather than

the straight sides of a beaker. In the case of an Erlenmeyer Flask they slope in a

cone shape to close towards the top of the flask. There are many types of flasks and Erlenmeyer Flasks are the most common. The narrow top allows mixing with reduced chance of spillage, and the smaller mouth can be topped with a cork, or in some designs with special joints for attachment to other lab tubing.

Erlenmeyer flasks are used for stirring or shaking where their narrow mouth openings can reduce spillage. They can be used for reactions, heating and most other functions. Erlenmeyer flasks should be made of borosilicate glass for safety purposes, although plastic versions are available for non-heating, less caustic experiments. These plastic versions often have screw on lids for vigorous shaking/stirring. The plastic used should be the more durable Polypropylene.

Graduated Cylinders:

Graduated Cylinders are used for more accurate measurement of liquids. While Griffin Beakers and Erlenmeyer Flasks may have measurement markings printed on them, they are more for general reference than accurate measurement. To properly measure liquid in quantities larger than 1ml an appropriate size cylinder should be used. Reactions should rarely be done in cylinders, and heating/shaking/stirring should not be done in them. The chemicals should be poured into a beaker or flask to do that. Cylinders are usually made of borosilicate glass, with either a 1 piece glass base  or a  glass tube inserted into a plastic base. The plastic base can make the cylinder easier to clean, but can also be more vulnerable to spilled caustic chemicals.

Completely plastic graduated cylinders are also available for those who want less glass breakage and aren’t using reactive chemicals. The plastic used can be either polyproplyene, which is translucent and can be tricky to read the measurements, or PMP which is clear but can be more expensive and more brittle.

Since graduated cylinders are used for measuring chemical quantities they have markings on them to note quantity of liquid, etc.  These markings are usually ascending but in some cases they may be ‘Double Scale’ where the 1 set of markings counts up and the other counts down. A lot of graduated cylinders just have one set of markings, however.

Most graduated cylinders sold are considered to be class ‘B’ quality. These are accurate for most purposes. More precise measurements  should use Class ‘A’ cylinders which usually has tolerances of about 0.5% for more accurate chemical measurement. These high tolerances come at fairly steep price, however.

Continue to Part 2!  More flasks and specialty glassware!

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