Ohio Volunteer Firefighter Practice Exam

What is the primary method of heat transfer when steel is heated?

1. Convection

2. Conduction

3. Radiation

4. Diffusion

The correct answer is: Conduction

When steel is heated, the primary method of heat transfer is conduction. Conduction occurs when heat is transferred through direct contact between materials, which is the case with solid materials like steel. In this process, the heat energy excites the atoms within the steel, causing them to vibrate more vigorously. As these atoms collide with neighboring atoms, they transfer some of their energy to them, and this process continues throughout the material. In practical applications, when a flame or another heat source comes into contact with the surface of steel, that heat travels through the steel by conduction. For instance, in firefighting scenarios, understanding how conduction works is crucial because it influences how quickly the metal can reach dangerous temperatures, potentially compromising structural integrity. Convection typically involves the transfer of heat through fluids (liquids or gases) and is not applicable to solids like steel. Radiation involves the transfer of heat in the form of electromagnetic waves, which can impact temperatures but is not the primary method for solid materials. Diffusion refers to the movement of particles from an area of higher concentration to an area of lower concentration and is not a method of heat transfer. Hence, conduction is the correct answer in this case.