Both the Earth and the International Space Station (ISS) receive their heat (energy) from the Sun. However, the way heat is transferred is completely different. Heat conduction and convection do not occur in space since there is no air in space. Heat transfers in space, which is a vacuum, only by radiation.
While cooking a BBQ, the grill may get hot enough to burn your fingers, but you could still touch the tip of the grill for just a brief second. The grill is conveying the heat it receives from the charcoal flame that surrounds the environment. The heat also transfers from the grill to the meat that youﾍre cooking. Heat conduction occurs between two objects that are touching each other.
A Charcoal fire can burn quite vigorously. The air, warmed by the burning charcoal, gets lighter and rises up, whereas cold air moves downwards since it is heavier than the warmer air. The air then starts warming up and then rises. Through this repeated process, eventually the total volume of air will gradually warm up. This movement of air and water, caused by heat, is called convection.
Substances, such as the BBQ grill and air, are needed to convey the heat in both heat conduction and convection. However, radiation is totally different from conduction and convection. Energy transfers by changing its form from heat into light (wave) The charcoal fire emits invisible light. When this invisible light strikes the meat, it turns back into a form of heat. Thus, the meat becomes cooked. In space, heat transfers only by radiation, which is a vacuum and where nothing exists to conduct the heat.