字幕列表 影片播放 列印英文字幕 So a while back I did an imploding drum experiment, but at the time, I didn't have a very good high speed camera. And so I used something called optical flow to interplay between the frames and basically just tries to add in what must have happened. But since it doesn't actually capture what happened, you can see the deck to warps the frame and looks really weird and unrealistic. So I've come down to the Cuesta con Science center in camera and I'm gonna shoot this again with their amazing high speed 1200 frames per second. Okay, we've got steam billowing out of the drum, so it's totally full of water vapor at the moment. Now I'm gonna take it off the heating element. Now we're gonna cool down all that water in there, which is gonna cause it to condense as it condenses, is gonna create a vacuum in there, which hopefully will get it to implode. Whoa! Oh, yeah. Ah, a lot of people think this experiment is just about showing the power of the atmosphere, but I think there's a more important consequence. It explains why a power station, for example, you need to cool the steam as it comes out of the exit. To turn over a turbine, you have to get very hot steam, and everyone appreciates. The steam needs to be incredibly hot as hard as you can make it. But on the other side of the turbine, you need to use a condenser to cool down that steam. And this is why. Because that creates this big suction. So not only do you heat up the steam so it pushes over the turbine, you also need to cool it down with God through the turbine. So you have a big change in energy, and that is what turns a turbine over. Now, of course, suction is just the word we use when a fluid flows from an area of higher pressure into an area of lower pressure, which you'd know if you've seen the sauces video on the space straw. The lowest pressure you can get in a gas is zero, a perfect vacuum, but you can actually get negative pressures if the fluid is a liquid and it's inside a tree. Now that's really suction, so click on the link in the description. If you want to learn more so that 20 leader drum was good, But perhaps this 200 leader drum will be better. But the question is, will it implode? I want you to place your bets now we have to gas heaters. You can see keeping up this drum. It's, uh, pretty hot. We have a bit of steam coming out the top, as you can see there in a moment, we're gonna pull it off these gas burners, seal it up and start cooling it down with water. The water vapor inside will condense, and we will see if the atmosphere can crush it. I'm cautiously optimistic. Round objects are incredibly strong under compression, as destined showed us with Prince Rupert's drop. But if you create just a little ding in a round object, it should significantly weaken the structure. And that's what the hammer is for. Well, that's how it should work in theory, anyway. Underwhelming science. The implosion happens so fast in just 25 thousands of a second that the water on the left hand side of the drum can't keep up. Have a look. Ah, human blink takes about 100 milliseconds. That's four times the time it took for the drum to implode, so it's literally blink and you'll miss it. So there we go. We showed that the atmosphere is powerful enough. Do crumple even this very thick, very big drum. When we later measured, we found that the drum had crumpled into a perfect equal lateral prism, which might not surprise you if, unlike by heart, you prefer your maths potatoes with a minimum amount of gravy. You see for a given perimeter the equal lateral triangle and closes the minimum amount of area of any regular polygon. So the drone was optimizing to make the minimum volume in its interior, which is what you'd expect because there's a vacuum in there. Isn't that awesome? That is awesome. Uh huh. That feels good. What? You really warm Now? You may have noticed that the big drum crumpled into an equilateral prism, whereas the smaller drum crumpled into something resembling a hexagon. So the question is, why were they crumple in different ways? I mean, one thing I was thinking was that perhaps they were created in different ways, so maybe they were welded in different points, and that explains the structure that we saw. But I'd like to hear your thoughts. Why do you think we saw these different crumpling patterns? Mean? Obviously, things with three corners are generally quite stable, so that may explain also why it crumpled just thio triangular prism. But I'd like to hear what you have to say, so let me know in the comments.