In reactions {explosion}|, temperature increase can increase reaction rate, which then increases temperature, which then increases rate, and so on. Gas production increases rapidly. Gas propels outward from center if reaction makes heat more rapidly than heat can dissipate by thermal radiation or gas loss. Randomly moving molecules tend to bounce outward, because surface area is greater toward perimeter and smaller toward center. Explosions require heat to stay high enough to burn gas before gas can move far.
burning
Burning does not explode, because gas has unconfined gas expansion or has much thermal radiation, so heat spreads out by thermal radiation or gas loss faster than reaction makes heat.
Ignition can spread flame through flammable gas at subsonic speeds {deflagration}|, as heat diffuses through gas. Gas expands evenly.
Ignition can spread flame through flammable gas at supersonic speeds {detonation}|, because shock waves compress gas. Detonation causes engine knocking, because gas expands unevenly.
In explosion-like reactions {implosion reaction}|, gas amount can decrease as temperature increase increases reaction rate, which then increases temperature, which then increases rate, and so on, because gas is reactant and products are not gases.
Outline of Knowledge Database Home Page
Description of Outline of Knowledge Database
Date Modified: 2022.0225