Hot plates are laboratory tools used to uniformly heat samples. Hot plates provide less heat, but do so without the danger associated with the open flame and higher temperatures of a Bunsen burner. Hot plate stirrers operate by generating a rotating electromagnetic field in the stirring heads. The liquid to be stirred has a magnetized stirring bar placed in it. The bar and therefore the liquid, is rotated by the magnetic field produced in the heads. Hot plates and hot plate stirrers are available that can perform the duties of each apparatus.
Hot plates and hot plate stirrers are available with a number of different heating top styles. The most common types include those constructed from aluminum, ceramic materials or enamel. Aluminum topped hot plates provide a rapid heating surface, which retains and distributes heat very well. Aluminum also lends itself to easy cleanup. However, aluminum tops do have one specific drawback. They do not perform well in conjunction with corrosive materials, which can pit and erode the aluminum head. While most devices are designed with safety structures to protect the internal electronics and circuits, if the head comes into consistent contact with such materials, its efficacy and performance lifetime will be drastically reduced. If the hot plate in question will be used to heat or stir corrosive materials, it is best to select ceramic or enamel topped devices, which do not react in the same way.
Hot plates are laboratory tools used to uniformly heat samples. Hot plates provide less heat, but do so without the danger associated with the open flame and higher temperatures of a Bunsen burner. Hot plate stirrers operate by generating a rotating electromagnetic field in the stirring heads. The liquid to be stirred has a magnetized stirring bar placed in it. The bar and therefore the liquid, is rotated by the magnetic field produced in the heads. Hot plates and hot plate stirrers are available that can perform the duties of each apparatus.
Hot plates and hot plate stirrers are available with a number of different heating top styles. The most common types include those constructed from aluminum, ceramic materials or enamel. Aluminum topped hot plates provide a rapid heating surface, which retains and distributes heat very well. Aluminum also lends itself to easy cleanup. However, aluminum tops do have one specific drawback. They do not perform well in conjunction with corrosive materials, which can pit and erode the aluminum head. While most devices are designed with safety structures to protect the internal electronics and circuits, if the head comes into consistent contact with such materials, its efficacy and performance lifetime will be drastically reduced. If the hot plate in question will be used to heat or stir corrosive materials, it is best to select ceramic or enamel topped devices, which do not react in the same way.
Both glass ceramic and enamel tops give hot plates excellent chemical and temperature resistance, and are easy to clean. They are also less like to conduct heat to the sides or edges of the hot plate, which could cause inadvertent burns to the unprepared user. Additionally, the neutral coloring of these devices allows for better visibility when studying a sample for color change, such as in titration.
When selecting between a number of styles of hot plates and magnetic hot plate stirrers, it is best to understand the specifics of the application at hand. More to the point, what types of samples will be used, through what temperature ranges will they travel, and at what rate must they be stirred (either to facilitate reactions or break down samples into their constituent parts).
