Final answer:
The primer's spark ignites gunpowder, causing it to rapidly decompose into gases, releasing chemical potential energy which results in a rapid expansion and explosion.
Step-by-step explanation:
The spark from the primer ignites the gunpowder, which rapidly converts to gases that expand and exert pressure. This process is the core of how firearms and fireworks operate. Gunpowder, comprised of charcoal, sulfur, and saltpeter (potassium nitrate), reacts violently upon ignition. During this reaction, chemical potential energy stored in the gunpowder is released, propelling the projectile or creating a loud explosion in the case of fireworks or firearms. The transformation involves the charcoal turning into carbon dioxide with potassium nitrate providing the necessary oxygen for the reaction to occur swiftly, while sulfur's role is to stabilize the mixture. While gunpowder played a crucial role in handheld firearms, continuous advancements have been made for greater effectiveness and reliability in weaponry and pyrotechnics.