4a) Campfires give off heat in different modes (conduction, convection, and radiation), each at different levels of heat, with conduction emitting the least amount of heat. With air being the conductor, there is little amount of conductive heat transfer as air lacks thermal conducting. The campfire also emits convection, but this heat only rises upward and never reaches you. The third form of heat, radiation, travels in straight lines. This means that if you were facing the fire, only the front side of your body will be warmed while your back will not be reached by the radiation.
4b) Aluminum foil has a low heat index. It doesn’t hold heat, meaning that it heats up and cools down very quickly. Unlike most things you’d place in the oven, the foil will not feel hot when you pull it out of the oven.
4c) The sun first emits thermal radiation, causing the temperature inside the car to increase. The car absorbs the radiation which then receives thermal energy. Conduction transfers heat from the car’s outer surface to the inner surface. The thermal energy is transmitted through the glass windows and is absorbed by the interior of the car (the darker the interior, the more heat absorbed). As the energy is transferred from the interior itself to the air inside the car during conduction, then convection begins. As air goes over the already hot interior surfaces, the air is warmed and the process is continued.
