Redox reactions between metals and metal oxides (thermite process)

The experiments described here are highly suitable for demonstrating the different affinity of various metals in view of oxygen. The less noble a metal is the higher its affinity to oxygen and the more thermal energy is released during its oxidation. The technical importance of the thermite process for the welding of iron parts is that it is relatively easy to produce large amounts of liquid iron and, thereby, to fill wider weld grooves. This is why this process is mainly used for welding thick steel beams, rail tracks, and machine parts.