What is a glass stirring rod and a rubber policeman and how are they used?

Answer 1

A stirring rod is a glass rod, typically about 6 inches to 1 foot long and 1/8 to 1/4 inch in diameter that can be used to stir liquids in flasks or beakers.

You can also use a stirring rod to help pour liquids without spilling. Because of surface tension, liquids tend to run down an object. So if you hold a glass rod vertically, with one end in the opening of the beaker or flask you are pouring into, and then hold the top end of the glass rod against the rim beaker you are pouring out of, the liquid will run down the rod and not spill. Be careful... it might take a little practice to get the proper technique!

Sometimes, an attachment called a rubber policeman added to the end of the stirring rod. It is used to transfer residues of precipitates or solids from the inside or beakers, flasks or other glass surfaces. They are often made from rubber, but plastic ones can also be found.

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Answer 2

A stirring rod is used in chemistry primarily to stir aqueous solutions, so liquid stuff...although I have used it as a means to smash things also...a rubber policeman is basically a chemists equivalent to a cooking scraper and is used it get as much of a mixture out of glassware, typically a beaker, as possible.