Hot air oven works on the principle of the dry air sterilization process through convection, conduction, and radiation. The heating elements heat the air inside the chamber, which may be circulated evenly within it with the help of fans such that the sample surfaces are exposed to hot and dry air. This exposure causes the heating of the external surface of items, and by the conduction process, the heat is transferred toward the center of the item. Likewise, in microorganisms, heat causes water inside them to evaporate, causing oxidative damage of cellular constituents, denaturation of proteins, and toxic effect of elevated levels of electrolytes and, ultimately, the death of the microorganisms.