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Watch This Model Rocket Engine Destroy a Fish Tank

Slow-motion video illustrates how rockets still function under water.

Few busted fishtanks have ever enjoyed so spectacular a sendoff as the one destroyed by the slo-mo fans over at YouTube's Warped Perception earlier this week.

The tank's last inhabitant was not a koi or a betta, but rather a model rocket engine that ignited in a blaze of glory while submerged under a couple of gallons of water. And the best part? We get to watch it all in satisfying slow-motion in near-divine 4K resolution.

Flames like we see here don't seem like they should be possible underwater. The trick, as it turns out, is that the rocket engine's built-in mix of sulphur, charcoal, and potassium nitrate effectively self-supplies the oxygen that a flame would otherwise need from the open air. Last month, in fact, Warped Perception showed how the rockets still work in a vacuum owing to the same principles.

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For the most part, the tank handles the pressure well. Eventually, though, the engine burns to the stage at which a proper rocket would shoot out small parachutes or smaller charges, and the tank spectacularly bursts under the pressure.