Change Agent

摘要

The copper earring you see here had already been glowing bright orange for half an hour when we took the photograph. There is no flame under it, no electric current through it. Underneath is a pool of volatile and highly flammable acetone, but the liquid is not on fire. So where is the heat coming from? Acetone vapor and oxygen from the air are combining and releasing heat on the surface of the copper, at a much lower temperature than acetone normally burns (but still hot enough to make the earring glow). The copper provides a sort of backdoor that overcomes the resistance (called the activation energy) that normally prevents acetone from reacting, except at higher temperatures.