How does a dynamite work?

Answer 1

Dynamite was originally made by soaking diatomaceous earth (aka kieselgur/kieselguhr), sawdust, or some other absorbent material with nitroglycerin. More recent formulations are based on dissolving the NG in nitrocellulose with some ketone. The chemical formula for nitroglycerin (NG) is C3H5N3O9. While NG can be combusted, the explosive (detonation) reaction comes from the decomposition of NG through the reaction:

C3H5N3O9 --> 3CO2 + 2.5H2O + 1.5N2 + 0.5O2

Lighting the dynamite on fire and waiting for the heat to trigger the explosive decomposition is very inefficient. Since NG is shock sensitive, the detonation is usually is triggered by inserting a blasting cap into a stick. When the much lower powered blasting cap explodes, it provides sufficient shock and heat to trigger the detonation of the dynamite.

It is important to understand that the explosion of dynamite is a detonation rather than a deflagration. Deflagration is an explosion where the reaction accelerates but the shock wave precedes the reaction front, compressing and heating the reactants in front of the shockwave. By contrast, in a detonation, the reaction crosses over the shockwave and thus as the reaction occurs, it is compressing the reactants between the shockwave and the reactant front. Another way to describe this is that deflagration explosions are subsonic and detonations are supersonic.

Answer 2

Dynamite works by utilizing the chemical compound nitroglycerin, which is absorbed into a porous material such as diatomaceous earth. When the dynamite is ignited, the nitroglycerin undergoes a rapid exothermic decomposition, producing a high-pressure gas that causes an explosion. This explosion releases a large amount of energy in a short amount of time, making dynamite a powerful tool for demolition and mining.

Answer 3

Dynamite

A slow detonating explosive with a great deal of force.

Excellant for blasting, quarying or other earth - rock moving effects.