Which effect arose as an unintended consequence when Song dynasty alchemists sought an elixir?

💡 Explanation

Early alchemists inadvertently created gunpowder during elixir experiments using sulfur, charcoal and saltpeter by uncontrolled combustion, a chemical chain reaction; therefore, the explosive compound resulted, rather than immortality, because the mixture's components exceeded reaction thresholds.

• Which consequence of thermal expansion posed a challenge to early ship chronometers during long voyages?
• Which mechanism limited the maximum span of early cast iron bridges (e.g., Iron Bridge, 1779)?
• Which manoeuvre becomes impossible on a Viking longship if the sail's brailing lines degrade?
• Which outcome resulted when ancient Mesoamerican chinampa farmers over-cultivated maize without nitrogen replenishment?
• Which risk increases upon the failure of Viking longship's sail-reefing mechanism?
• Which navigational error increases after repeated mechanical chronometer shocks during rough ocean voyages?