The Backyard Scientist has tackled some pretty crazy experiments, but in this video he's finding out what happens when you throw a dry ice bomb into a pool… in slow motion. I know what you're thinking, it sounds kind of pointless, right? But the results are actually pretty incredible, and they reveal some fascinating physics of underwater explosions.
So first of all, 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. This is because the dry ice is sublimating into a gas as it quickly warms at room temperature, and there's simply not enough room in the bottle to fit all that gas.
While the explosion itself is pretty cool, 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. As you can see in the footage above, the explosion is so powerful 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 because 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.
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 video above 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.
And just in case you were wondering, THIS is what happens when you shoot an AK-47 underwater, thanks to Smarter Every Day: