What is the function of a heating block?

A heating block is generally found in a laboratory, and it is used to warm, cool, or perhaps maintain the temperature of samples, specimens or the like.

A heat block generally has a "base" of sorts with something like a thermoelectric heater (perhaps a Peltier heater/cooler) in the device. The block itself fits into the base, and it is held at a fixed temperature by virtue of the control circuitry that operates the base. The unit responds to input from someone who enters commands on a keypad or the like. Additionally, the block is sized and shaped to hold sample containers. Different blocks can be placed into the base, thus there is flexibility for variation in the sample containers. Use the link below to see some images of heating blocks to lock in the information.