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Why is it when you touch a hot burner your finger burns? Why when you turn up your furnace does your house warm up? When you flip on the light switch why does the room instantly light up? It is all caused by three methods of energy transfer. The first method of heat transfer is called conduction. The second is convection, and the third is radiation. Conduction The definition for conduction is passage of energy through a material by direct collision of particles. This is like touching a hot burner; the energy from the burner is transferred to your finger, and it "cooks" your finger!  The definition for convection is the process of transferring heat by the circulating motion of particles. This could be compared to when your house is cold and you turn up the thermostat; in a little while your house feels warmer. This is an example of convection; the heated particles of air from the furnace slowly move around your house from the currents and warm it up as they move through it.  The definition for radiation is the transfer of energy in a wave-like form. When you turn on a flashlight the radiation waves of light travel at light speed (300,000 km/s) in the direction you are pointing the flashlight. The radiation waves can bounce, be absorbed or go through things. Radiation is the only one of the three heat transfer methods that can travel though a vacuum. It does not require particles to work.  |