At the Hoover Dam, you can actually pour water straight up into the sky. No lie. And there’s a cool little experiment you can do that will prove it. All you have to do is open up a bottle of water, reach out over the edge of the dam, and start pouring it out. Instead of trickling down its concrete wall it will reverse course and shoot up into the air.

Check it out:

It’s not because the Hoover Dam happens to be built on lay lines or there’s some bizarre anti-gravity trickery going on. It’s because of the crazy powerful updraft that big dams can generate. Keep your eye on the right-hand side of the video and you’ll notice the water isn’t the only thing affected: the girl’s ponytail is getting blown around like crazy, too.


This isn’t just something that happens at the Hoover Dam, and you can use things other than water bottles to see how powerful the air currents are. Check out what happens when this dude gets a basketball spinning and then lets go over the side of the Gordon Dam in Tazmania (around the 24 second mark):

No, it doesn’t float back up like water does… but damn, does it ever travel a long way — and it gets going fast enough to skip across the surface of the river! You can thank the Magnus Effect for this particularly cool bit of video.