Final answer:
Cooking meat directly under a high-temperature source like a flame or an electric heating element is known as broiling, a process that utilizes radiation for heat transfer and can form harmful chemicals that increase cancer risk.
Step-by-step explanation:
Cooking meat directly under a flame or electric unit is called broiling. Broiling is a cooking method that utilizes radiation as the dominant method for heat transfer. A gas flame or electric heating element positioned above the food generates a very high temperature, which cooks the food primarily through the energy transfer of radiation. Unlike conduction, where heat is transferred through direct physical contact, or convection, which involves the movement of hot air, radiation cooks the food without a medium, allowing for quick and intense heat application directly to the food's surface.
When broiling meats, high heat is used, which can lead to the formation of polycyclic aromatic hydrocarbons or heterocyclic aromatic amines, chemicals that may increase cancer risk. In contrast, other methods like smoking meat can extend its shelf life and enhance the flavor without the high heat of broiling.
Conduction is another heat transfer method, illustratively shown through the heat transfer between an electric stove burner and the bottom of a pan. This method relies on direct contact, with different materials affecting the rate of heat transfer, such as a thick wool sweater slowing down the loss of body heat in winter.