Why are gases poor thermal conductors?
There is no continual flow of ions/electrons to act as a conductor. All the gases have localised electrons, meaning they don’t move around. Even if we boiled ionic and metallic substances which do conduct electricity, the gases would diffuse into the atmosphere, giving no continual flow. In addition, the composition of covalently bonded molecules in air would make it difficult for any others to conduct electricity.
The molecules of gas have a comparatively large space between them. Conduction occurs only in solids which have closely packed molecules who’s motion is restricted to vibration in the same position within the solid mass. The addition of heat energy, due to this compactedness, is translated to Kinetic Energy (greater vibrational motion) which is immediately transferred to neighbouring molecules and the Heat Transfer by Conduction is Achieved. Conduction is the Fastest form of Heat transfer. Convection, heat transfer in fluids (Liquids and Gases) is due to rising currents of fluid due to decrease in Density. Cooler fluid moves in to replace the rising current of fluid. This too, is heated and rises and a circulatory motion is set up within the Fluid. Radiation, the slowest of the Heat Transfer processes will only heat substances ‘or bodies” in the direct path of the Heat Rays. Stand in front of a fire on a cold night. Your front will become warm while you back remains cold. The Sun or an
