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This is one of the most common types of laboratory glassware, which is used by many scientists every day all over the world. They are typically cylindrical in shape, with a small spout for easy pouring, and are used for stirring, boiling and crystallization. They can hold various capacities from 50 ml to a litre.
Another feature of the common beaker is the fact that you can measure capacities and the amount of liquid in a beaker, however use the measurements as an estimate rather than extreme accuracy.
2. Conical Flasks ~ Erlenmeyer Flask
These flasks have a conical shape, hence the name, conical flask. However, the true name of this commonly found flask is the Erlenmeyer Flask and has three distinct variations. The reason an Erlenmeyer Flask has a conical shape is because it is possible to put a cork on the opening for heating. Beware, do not boil water using the flask, as it could cause a build up in gases, leading to explosion.
These three variations can be seen in the picture to the right, the most famous being the narrow neck Erlenmeyer flask.
One of the most famous uses of the conical flask is in a titration where an acid is titrated with a base, therefore giving a salt plus water. The flask is used to store the base whilst the acid is stored on top, in a burette which drops into the base.
3. Graduated Cylinders
These glass cylinders are used to accurately measure a volume of liquid. You simply fill the cylinder to your desired amount into the cylinder, and calculate how much that is. They are sometimes used to calculate the volume of an irregular shaped solid. This is done by measuring the amount of displaced water that rises higher, when the solid is lowered into the water. So, let's say that the amount of water at first was 50 ml. Then, a small stone is lowered into the water and the water rises up to a level of 65 ml. We then subtract 50 ml from 65 ml, and we are left with 15ml which is the volume of the stone.
Graduated cylinders are not used for exact accurate measurements to the nearest millilitre but are more accurate than that of a beaker or flask. They come in a variety of capacities from 50 millilitres to 1 litre.
4. Test Tube ~ Boiling Tube
A test tube is a long slender tube which is used for storing, mixing chemicals during a laboratory experiment. They can be put into a test tube rack, or clamped when not in use, or for use in an experiment. A test tube is a very common piece of glassware and comes in many shapes and sizes.
For example, a test tube is very slender, whilst a boiling tube is a little wider and thicker, for use in boiling.
5. Watch Glass
This is a very thin piece of glass that is barely concave, with a little dip in the centre to allow for storage of chemicals and powders. It is also used for evaporating liquids such as evaporating salt from a sodium chloride solution, to cover beakers and for weighing substances.
The reason it is called watch glass, is because of the concave-convex shape it has, which is distinctly similar to the piece of glass used in a watch.
6. Evaporating Dish
This is a dish which, as the name suggests, is used for evaporating and crystallization. An example is when a sodium chloride solution is left in the dish, and the next day, table salt is left. It is made of porcelain and has two features which make it suitable for evaporation.
- The flat and large base encourages evaporation.
- Once the water has evaporated, it will not condense and flow back into the solution like beakers or conical flasks.
To quicken the evaporation process, some scientists place a Bunsen Burner flame directly under the evaporation dish which is on a tripod and wire and gauze. This will cause the water to heat a little more and evaporate. The main thing is not to let it boil as evaporation is at a temperature lower than the boiling point at the surface of the liquid.
7. Petri Dish
A petri dish is a transparent glass or plastic dish that is used to culture cells. They are commonly used in scientific research, biochemistry and microbiology laboratories. One of the common uses of petri dishes is to see the kinds of bacteria to be found in the air or in soil.
Bacteria in a Petri Dish
8. Liebig's Condenser
This is used as part of distillation which condenses the evaporated off water back into liquid form. It is a very common condenser, which turns water vapour into water droplets through condensation. The condenser is kept cold by the constant flow of cold water which is connected to a tap. The tap is always connected to the lower opening and the cold water goes through an outer tube. The main purpose of a Liebig's Condenser, is in distillation where both the water and salt need to be saved. The water evaporates and turns to steam from the solution and goes up and into the condenser which is cold through cold water in the outer tube. The water vapour condenses and forms tiny little water droplets which flow into the flask.
A burette is a long slender tube which is used to dispense drops of liquid or chemicals. It also has an exact markings for precise measurement and can be used to measure capacity. The most famous use of a burette is in that of a titration, where the burette is placed on top to dispense the acid into the base.
It contains a 'tap' or 'switch' which when is turned to a horizontal position closes off the flow of liquid. When the tap is twisted vertically, this opens the tap and allows the flow of the liquid. It is very precise, and has to be as titrations need highly precise equipment.