Which device uses a rotating magnetic field to stir liquids?

The device that uses a rotating magnetic field to stir liquids is a magnetic stirrer. This piece of laboratory equipment consists of a magnetic stir bar that is placed in the liquid to be stirred, and as the magnetic stirrer generates a rotating magnetic field, it causes the stir bar to spin. This motion effectively mixes the liquid uniformly without the need for mechanical stirring, making it particularly useful for solutions that require gentle mixing or where contaminants from mechanical stirring might be a concern.

Magnetic stirrers are commonly employed in various laboratory settings for tasks such as dissolving substances, mixing reagents, or maintaining a homogeneous solution during reactions. The design allows for precise control of the stirring speed and often features settings for adjusting the temperature, which can be critical when performing experiments that require consistent conditions.

In contrast, other devices do not serve the same function as a magnetic stirrer. A microcentrifuge is used to spin samples at high speeds to separate components based on density but does not mix liquids through a rotating magnetic field. A pipet aid is designed to assist in the manual transfer of liquids using a pipette, while a test tube holder simply secures test tubes in place for handling but does not involve any mixing mechanism. Each of these other options has