a bomb designed to cause fire?

Answer 1

Incendiary Weapons
The purposes of incendiaries are to cause maximum fire damage on flammable materials and objects and to illuminate. Incendiary agents are used to burn supplies, equipment, and structures. Initial action of the incendiary munition may destroy these materials, or the spreading and continuing of fires started by the incendiary may destroy them. Even experienced troops may suffer increased battle fatigue when confronted with a surprise enemy weapon, tactic, or attack. Examples include napalm bombs (Israel against Egypt, US against North Vietnam).

The use of flame weapons, such as Fougasse, the M202A1 Flash, white phosphorous, thermobaric, and other incendiary agents, against military targets is not a violation of current international law. They should not, however, be employed to just cause unnecessary suffering to individuals. The use of flame weapons should be addressed in the ROE. Flame weapons are characterized by both physical (flame and overpressure) and psychological casualty-producing abilities.

Flame does not normally need to be applied with pinpoint accuracy to accomplish its mission. Efforts must be made to ensure that certain types of flame munitions effects do not spread to structures needed by friendly forces. Large fires in urban areas are catastrophic, and these fires can create an impenetrable barrier for hours.

.................the rest of the story here............
http://www.globalsecurity.org/military/systems/munitions/incendiary.htm

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Answer 2

You can go with the classic molotov cocktail, or my personal favorite - Gas + Soap == BURNY FUN!!! Please try to make the question a bit clearer - as it is, your question is ambiguous and doesn't really ASK anything.

Answer 3

What about them? Most of them use Napalm, thermite or something similar.

Answer 4

Do you mean a pyro-bomb?

Answer 5

...is called an incendiary device.