The Backyard Scientist has been busy finding out what happens next when you throw liquid nitrogen and dry ice into a swimming pool.
To start with, he takes some dry ice and puts it into a plastic bottle, before attaching a weight to the bottle, closing the lid and quickly throwing the whole thing into his swimming pool. As you might imagine, within a few seconds, a pretty impressive explosion sprays up.
In the footage below, the explosion is so powerful that you can actually witness it traveling through the water. But instead of just moving outwards like a normal shockwave, the explosion expands and shrinks a few times before the gas eventually reaches the surface of the water.
This is due to the gas released by the explosion rapidly pushes outwards until the water pressure becomes greater than the force of the expanding gas. At this point, the water then pushes the gas back inwards, until the pressure becomes so great that it overcomes the water pressure once more.
In Chemistry, when carbon dioxide is cooled past -78.3oC (-109oF), it becomes dry ice and freezes into a solid. Warm this solid up and the dry ice sublimates (goes from solid to gas, instead of from solid to liquid to gas). If it sublimates inside a sealed container, the pressure inside will also increase, which can cause the container to burst.
While the explosion itself is pretty incredible, the Backyard Scientist also puts some slow-motion cameras underwater to see what’s going on beneath the surface, and this is where it gets really interesting. Even more impressive is the fact that you can actually see this happening in the wave patter on the surface of the pool, too.
Check out the epic video below to see the explosion in action. If seeing what happens to the balloons near the exploding bottle isn’t enough of a warning, please don’t try this at home.