Sand bath

A sand bath is most commonly used in conjunction with a hot plate or heating mantle.

A beaker is filled with sand or metal pellets (called shot) and is placed on the plate or mantle.

The sand or shot then conducts the heat from the plate to all sides of the reaction vessel.

This technique allows a reaction vessel to be heated throughout with minimal stirring, as opposed to heating the bottom of the vessel and waiting for convection to heat the remainder, cutting down on both the duration of the reaction and the possibility of side reactions that may occur at higher temperatures.

Sand baths are one of the oldest known pieces of laboratory equipment, having been used by the alchemists.