In laboratory and chemistry experiments, it is very important that solutions and mixtures get mixed completely. This is usually not executed properly when the stirring occurs by hand, which is why different machines have been developed to make sure that the stirring is thorough and done right. Some machines are just standard-style mixers, like the type you would use to make cookies. However, there are also magnetic stirrers.
Magnetic stirrers can usually only be used on small mixtures, and do not work well in thick liquids. However, in the right circumstances, they can be used to great affect to ensure that the liquid is thoroughly and completely mixed.
A magnetic stirrer operates under a fairly simple design. Basically, a rotating magnetic field is used to rotate a small stir bar that is placed in the solution. The tiny bar spins, creating a lot of rotation in the liquid, which causes it to mix together. The spinning motion could be caused by either rotating magnets, or by electromagnets, and they usually also have a hot plate to set the mixture on so that it can be heated as it stirs. Usually, liquids will mix together better if the temperature is higher.
There are several advantages to using a magnetic stirrer in a laboratory or chemistry set type application. For one, these are simple machines that do not require the use of huge, mechanical stirrers. Two, the small rotation bar placed inside the liquid is smaller and much easier to clean than a large stirrer. Three, there is no grease or lubricant on the small rotational bar that could cloud the results of the experiment. All big mixers require at least some type of lubrication. And finally, they are so easy to use and compact in size that they are incredibly easy to use overall.
The downsides to magnetic stirrers is that they can only be used in smaller amounts of liquid. For anything that will require the stirring of a large amount, a regular mixer might need to be used.
Magnetic stirrers are also called magnetic mixers by some people (or a variation of a hot plate), and they were developed back in 1944 by a man named Arthur Rosinger. The plastic coating that covers the magnetic bar in most magnetic stirrers was not developed until later on in the 1940s, and was invented by a man named Edward McLaughlin as a separate project. It was named a “flea” actually, because if the speed gets turned up too fast, it bounces around in the glass like a small flea.
If you do a lot of biology or chemistry experiments, then a magnetic stirrer is something that you may benefit from owning. These devices are actually not too expensive, considering what they are, and you should not have trouble finding them online in various scientific stores.
You can also get them from laboratory supply companies. Making sure that liquids are completely mixed is essential to having results as precise as possible, which is precisely the reason why these magnetic stirrers and mixers are so popular for use in chemistry and biology experiments.