Test Tube, Porcelain Spot Plates, And Watch Glass

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Laboratory equipment that can be used as a container to identify a chemical substance is test tube, porcelain spot plates, and watch glass. The test tube is made of glass, transparent, colorless, can be heated in a direct flame or heated in water or in a tool such as autoclave in accordance with the temperature needed. The test tube is shaped like a pipe of which one end is open or has no lid. test tube has a diameter of approximately 2 cm with a height of 10 to 15 cm. The test tube is used for mixing or reacting chemicals, or can be used as containers agar in microbiology lab with a lid that is used is a sterile cotton.

If in hot conditions, tube clamp made of wood can be used to hold the test tube. Clamp tube shaped like a pair of scissors, but not sharp, in the middle there is a perforation circle as a place to clamp the test tube. Tube clamp has a thickness of 1 cm and colored wood is light brown. a tube rack is used To enforce or holding a test tube so it does not roll or fall. Tube rack made of wood or stainless steel, in the form of rectangular boxes that have shelf-perforation perforation as a place to enter the tube. The test tube can also be used as a container of the pipette, such as graduated pipette, Pasteur pipette, and volumetric pipette. So that the tip of the pipette that is being used is not dirty. How to use it is insert the tip of a pipette to take a liquid and then put into a test tube, these two tools can be stored in a table or can be stored in a tube rack, so that the position of pipettes and test tubes in a standing position.

When mixing two different liquids in test tubes, it's rather difficult to stir, since the diameter of a test tube is small, if inserted stir bar will increase the volume of the substance contained in a test tube and might overflow. If the test tube shaken by hand, the two fluids will be mixed but not optimal. the centrifuge machine is to stir the liquid in a test tube so it can mixed perfectly.

Centrifuge machine is a machine that in the middle of it there is a circle made by metal plate coated with rubber. This tool has a working principle based on centrifugal. The metal is rotating at high speed. Speed can be adjusted as needed. If a test tube putted on top of the substances contained in the tube will spin faster and stirred perfect, but the test tube must be held in tandem. If there are deposits of a substance in a test tube, the sediment will condense and separate from the solution.

The test tubes can also be used as a agar container in the microbiology lab. How to use it is, pipette 10 ml of agar solution, and then insert it into the test tube. Then close the tube with cotton so that there is no substance that can enter into the tube or out of the tube. After that unites the test tubes containing a agar solution, for example 10 test tubes and tie with using rubber bands or straps. So that it can stand. Then wrap in paper and put in the autoclave to sterilize.

After sterilization in autoclaves, test tubes will be hot and the agar in liquid form. After stored at room temperature until cool, put them in the refrigerator so it can be used in the long term. If the media want to be used, then grab a solid agar medium from the refrigerator and open the paper wrapping paper and place the test tubes in a rack tube. Do not open the cotton cover tube before it will be used to keep the media remain stable.

Before and after using the test tubes, it must be washed with water and then with soap, and the inside of the tube thoroughly with a brush to clean the tube. Then the last rinsed again with water. Then rinsed with distilled water three times or dried in an oven. Or it could be drained in a tube rack by position upside down, so that the water in a test tube will go down and test tube will dry quickly.

Another tool that can be used to identify a substance is porcelain spot plates. It is made of white porcelain, a box-shaped measuring 10 cm x 10 cm with a thickness of 1 cm. At the top of the porcelain spot plates, there are small hollows semicircle with a diameter of 1 cm and depth 0.5 cm. porcelain spot plates are widely used in qualitative analysis to identify the chemical substance.

How to use the porcelain spot plates that take the substance to be identified, for example, in the form of a solution, using a Pasteur pipette and drops into one of the hollow of porcelain spot plates 2 to 3 drops, then grab a reagent with a Pasteur pipette and dropped into the above sample solution was 2 to 3 drops, See the color changes or other reaction was made. Before and after using porcelain spot plates, it should be washed with water and then with soap, and the inside of the hollow tube thoroughly with a brush to clean. Then the last rinsed again with water. Then dried in an oven or wiped with a tissue.

Another tool that can be used in identifying a substance that is a watch glass. This glass existing circular hollow in the middle. Watch glass has various size diameter of 2 cm, 5 cm, 7 cm, 10 cm, 15 cm, and etc. Watch glass are made of glass and transparent or colored green. How to use the watch glass that take the substance to be identified is, for example, solids are taken with a spoon as much as 1 gram, or a solution is taken using a pipette 1 ml, place it above the watch glass, then grab a reagent with a pipette and drop it on top of the watch glass containing sample earlier. See the changes or the reaction made.

Before and after using the watch glass, it must be washed with water and then with soap, and the inside of the hollow tube thoroughly with a brush to clean. Then the last rinsed again with water. Then dried in an oven or wiped with a tissue. Watch glass also has other functions which can be used as a cover glass beaker or Erlenmeyer. Can also be used as a container for placing solids sample or chemicals.

That is part of the lab tools that can be used to identify chemical substances in a sample or qualitative analysis.

Beaker Glass and Erlenmeyer Flask

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In any lab glassware must be on this, the beaker glass and Erlenmeyer flask. Both of them have a scale but cannot be used to measure liquids accurately, only estimates. Beakers are commonly made of glass (today usually borosilicate glass), but can also be in metal (such as stainless steel or aluminium) or certain plastics (notably polythene, polypropylene, PTFE). A common use for polypropylene beakers is gamma spectral analysis of liquid and solid samples. Beaker made of glass can be used for a variety of liquids and solids, while the beaker plastic or metal only for liquids or solids that have a neutral, such as saline or distilled water, this is done to prevent unwanted reactions between acids or bases with a beaker of plastic or metal.

Beaker has a variety of sizes, among which 50 mL, 100 mL, 200 mL, 250 mL, 500 mL, 1000 mL and so on. For instance, a 250 mL beaker might be marked with lines to indicate 50, 100, 150, 200, and 250 mL of volume. These marks are not intended for obtaining a precise measurement of volume, but rather an estimation. Most beakers are accurate to within 10%. Beaker used for various purposes, such as making the solution both of liquids and solids, weighing solids, as a container to hold the solution, even as a temporary waste container. Beaker does not have a lid. The tools used to seal glass beaker namely watches. Watch glass is a glass circle like a plate which at its center curved downward. At the top of the beaker there is a mouth like a teapot to facilitate fluid out of the beaker.

How to use the beaker as a container for weighing is sure beaker clean, had been washed with soap and scrubbed using a brush tube. Dry the beaker using a tissue. After it was placed on top of a dry watch glass, this is done to prevent other substances into the beaker during and after the weighing process. As the container to create a solution that is open beaker containing solids and closed the watch glass, pour distilled water or other solvents into the beaker until all solids submerged, then stirring using a stirring rod, stirring time try not to make a sound that is too noisy. The sound caused by friction stir bar in the beaker.

After all solids dissolved, add distilled water or other solvents to the extent desired. Beaker used as a container for storing temporary solution, or as a temporary waste container must be kept closed to prevent other substances into the beaker. And give the label on the beaker if necessary, to prevent the exchanged solution. To take a solution or make a solution of solids that will be damaged if exposed to light, the beaker can be wrapped with black carbon paper. But now there are tools included brown glass beaker for this solution or solids.

Other glassware in general at the lab is Erlenmeyer flask. Erlenmeyer flask made of glass, shaped like a pipe, but getting to the top, the diameter is getting smaller. At the top there is no mouth teapot like on beakers and do not have a cover. It is named after the German chemist Emil Erlenmeyer (1825–1909), who created it in 1860. Erlenmeyer most widely used in the titration process. This is because when Erlenmeyer shaken by hand, or splashing out a solution opportunity is very small as the diameter of the top of the Erlenmeyer more smaller than the diameter of the bottom.

And Erlenmeyer flask has a comfortable neck to grip by hand. At the time of titration, Erlenmeyer has shaken with one hand, and rocked in a direction that is clockwise or vice versa. This is done to stir the solution in Erlenmeyer with the reagent from the burette. In addition, magnetic stirrer can be used for stirring. Insert magnet into Erlenmeyer flask and place it in a magnetic stirrer and then turn them on. Magnet Erlenmeyer will spin and the solution will be mixed. In addition to rotating, magnetic stirrer can also heat the solution up to a certain temperature. Erlenmeyer shake pace was not too fast and not too slow. Thus the solution in Erlenmeyer is mixed perfectly.

Erlenmeyer has a wide range of sizes among which 100 mL, 250 mL, 500 mL, 1000 mL and so on. For instance, a 5000 mL beaker might be marked with lines to indicate 100, 200, 300, 400, and 500 mL of volume. These marks are not intended for obtaining a precise measurement of volume, but rather an estimation. There are 2 types Erlenmeyer, which is transparent and brown. Erlenmeyer brown used for the solution that is easily damaged by light. Erlenmeyer also be used to prepare a solution which must be heated, when the water bubbles that arise because of the heat, it will be splattered against the wall and back again to Erlenmeyer bottom, this prevents the solution splashing out Erlenmeyer.

Erlenmeyer flasks are also used in microbiology for the preparation of microbial cultures. Plastic or glass Erlenmeyer flasks used in cell culture are sterilized and may feature vented closures to enhance gas exchange during incubation and shaking. The use of minimal liquid volumes, typically no more than one fifth of the total flask volume, and baffles molded into the flask's internal surface both serve to maximize gas transfer and promote chaotic mixing when the flasks are orbitally shaken. The oxygen transfer rate in Erlenmeyer flasks depends on the agitation speed, the liquid volume, and the shake-flask design. The shaking frequency has the most significant impact on oxygen transfer.

Oxygenation and mixing of liquid cultures further depend on rotation of the liquid "in-phase", meaning the synchronous movement of the liquid with the shaker table. Under certain conditions the shaking process leads to a breakdown of liquid motion – called "out-of-phase phenomenon". This phenomenon has been intensively characterized for shake flask bioreactors. Out-of-phase conditions are associated with a strong decrease in mixing performance, oxygen transfer, and power input. Main factor for out-of-phase operation is the viscosity of the culture medium, but also the vessel diameter, low filling levels and/or a high number of baffles.