Ladder-up reaction

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A ladder-up reaction is a chain reaction typically used to ignite a hotter-burning substance from a cooler-burning substance whose burning temperature overlaps with the fire point of the hotter-burning substance.

[edit] Examples

A basic example of a ladder-up reaction is using kindling to start a fire. Whereas wood is rather troublesome to light using a match or lighter, paper ignites quite readily. When it is burning, its temperature will go up, overlapping the fire point of the wood. The ladder-up reaction is:

Match → Paper → Wood

Another example is the welding compound thermite. Thermite, a mixture of powdered aluminium and rust has an exceedingly high fire point. It can be ignited by flaming magnesium, which in turn can be ignited by a propane torch, which in turn can be ignited by a simple household match. The ladder-up reaction is:

Match → Torch → Magnesium → Thermite

A ladder-up reaction is not necessarily combustive. A hydrogen bomb is a non-combustive example of a ladder up reaction. A Hydrogen bomb must be started by a nuclear fission reaction, which must be started by conventional (although powerful) explosives. The ladder-up reaction is:

Explosives → Nuclear Fission → Nuclear fusion