What is the purpose of the rubber policeman on the stirring rod?

What is the purpose of the rubber policeman on the stirring rod?

Rubber policeman attached to glass rod facilitates scraping and mixing. Stirring rods are made of soft flint glass with both ends fire polished and rounded. Policemen are made of natural rubber.

What is the meaning of stirring rod?

A glass stirring rod, glass rod, stirring rod or stir rod is a piece of laboratory equipment used to mix chemicals. They are usually made of solid glass, about the thickness and slightly longer than a drinking straw, with rounded ends.

How much does a stirring rod cost?


Cat Code Description Price
GSR006-PK Glass Stirring Rods Regular Price $3.36 $3.02
GSR008-PK Glass Stirring Rods Regular Price $4.40 $3.96
RHGSR1-PK Rubber Policeman $4.72 $4.25
GSR010-PK Glass Stirring Rods $4.86 $4.37

What do you use a rubber policeman for?

A policeman is a hand-held flexible natural-rubber or plastic scraper. The common type of it is attached to a glass rod and used in chemical laboratories to transfer residues of precipitate or solid on glass surfaces when performing gravimetric analysis.

What is the role of policeman in gravimetric analysis?

Use a rubber policeman (click for video) to make sure all the precipitate has been transferred from the beaker to the filter. It is important that the precipitate is quantitatively transferred to the filter. If any remains in the beaker, the mass obtained will be inaccurate.

What is the purpose of stirring?

Stirring allows for the homogenization of mixable liquids and the stir-up of solid particles in liquids. Differences in temperature or concentration are balanced more efficiently during stirring. Additionally, the stirring of liquids speeds up the dissolution process and increases the speed of chemical reactions.

How do you clean a stirring rod?

The stirring rods get wet with each usage, and if not properly cleaned, will contaminate the next solution. A simple way to keep stirring rods clean is to place them in a beaker of clean distilled water and swirl them about after each use. The contamination will be highly diluted and can remain in the water.

What are glass fishing rods used for?

Since the glass rod is more flexible, it naturally gives causing the fish to get the bait in his mouth instead of ripping the hooks out. They also improve casting distance due to their slingshot like ability. This allows for further casts and is crucial when throwing larger crankbaits.

Why are they called rubber policeman?

particles adhering to the glass must be removed by means of a so-called policeman, which is made by inserting the end of a rather thick large-sized glass stirring-rod into a short piece of rubber tubing. It is like the police in that it gathers up any stray or escaped particles of precipitate on the beaker wall.


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