Video: Drop a lit match in water, and it will immediately be extinguished. But model rocket engines, made mostly of potassium nitrate, sulphur and charcoal, will burn all the way through even when completely submerged. As this high-speed footage reveals, to test a rocket engine’s apathy to H2O, you’ll want to find something stronger than a glass fish tank for your experiment.
YouTube’s revealing how exactly they burn, and what makes them so potent. For the most part this experiment seemed pretty docile, with the rocket engine just churning up the water as it burned. But once the engine’s detonation charge goes off, which is used to eject parachutes or activate other stages, the fish tank instantly shatters into a thousand shards of glass. It’s a complete write-off, but the slow-motion footage of the explosion was worth the loss.