Why is it possible to briefly touch a loaf of bread that is baking without being burned but not the metal pan that it is in?

Answer 1

This is a physics question relating to specific heat and conductivity. Specific heat refers to the amount of energy it takes to raise or lower the temperature of a given mass. For example it takes a very larger amount of heat to raise the temperature of a gram of water one degree than it does to raise the temperature of a gram of aluminum one degree (about 4.6 times as much). Bread has a low specific heat. This means that while the bread crust may be 200+ degrees it doesn't really contain that much energy. Conductivity refers to the capacity to transfer heat energy quickly. Things like metals are highly conductive. For example if you heat the center of a pan the edges will quickly become hot also because the metal easily conducts that heat from the heat source to the edges of the pan. On the other hand there are materials that conduct heat very poorly. Wood for example. You can hold on to the end of a stick while the other end is on fire and it will never even feel warm (until the flame burns you). Bread is a poor conductor. This means that bread both contains little energy and does not conduct that energy into your finger very quickly. You can handle hot bread. Metal contains more energy (depending on the metal) and it readily conducts that energy into your finger burning you.