The hammer-feather drop in the world’s biggest vacuum chamber [video]

[paddyoloughlin]

I wish the producers were less enamoured of their slow-mo and showed us the whole thing in real-time.

The "weird" thing is seeing feathers plummet to the ground and I wish we got to see more of that.

[zelos]

This is a Brian Cox show we're talking about, not a science show. I'm surprised there weren't more slow mo shots of Cox doing his "boyish wonder" face.

[thaumaturgy]

Somebody on Reddit took that scene, sped it up to something close to normal time, and made a gif:

http://gfycat.com/GentleMeaslyFattaileddunnart

[mhartl]

Not wanting to wait through the prologue, I skipped ahead in the video, where I searched in vain for the real-time drop. It's bizarre that they apparently didn't show it even once, especially since it can't have taken more than a few seconds (the chamber's height is 37.2 meters [1], so t_max = √(2h/g) = √(2×37.2/9.8) = 2.75 s).

[1]: http://www.dailymail.co.uk/sciencetech/article-2819205/Testi...

[danielweber]

With the HTML5 player you can double the speed; it's entirely in browser, so you can probably capture the Javascript event and make it go at 5x or 10x or whatever is needed to play at full speed. (It'll be up to you to then dub in Yakety Sax.)

[apcherry]

For me the "weird"/unusual/interesting thing is seeing the feathers bounce after hitting the ground.

[shangxiao]

I actually like the slow-mo as it reaffirms the fact that there is no air in that chamber.

When the feathers first drop you see a slight sway in the feathers, but only due to the acceleration. It's actually quite a sight to see feathers accelerate so quickly and stay so still.

[kyberias]

Exactly. I was frantically searching the video for this. Did they show it?

[blutack]

Seeing as the original site has now fallen over, the actual youtube link is

https://www.youtube.com/watch?v=E43-CfukEgs

[nmeofthestate]

And for the violently impatient, the actual drop: http://youtu.be/E43-CfukEgs?t=2m52s

[pshinghal]

Certainly a lot of us know what to expect in this experiment, but the thing I never really thought about was a that the feathers would bounce back up after impact. Seems obvious in retrospect, but it was pretty cool to see.

[revscat]

Commander David Scott did this same experiment as part of Apollo 15 in August of 1971, in an even larger vacuum:

https://www.youtube.com/watch?v=KDp1tiUsZw8

[ColinWright]

That's one reason why I posted the link to this site, rather than directly to the YouTube video, as explained here:

https://news.ycombinator.com/item?id=8556363

The text of the site I submitted has kindly been posted by DanBC[0] here:

https://news.ycombinator.com/item?id=8556409

[0] https://news.ycombinator.com/user?id=DanBC

[paddyoloughlin]

I love how professionals who work at that facility and have probably deeply understood those principles for decades still display so much wonder at seeing this experiment with their own eyes.

[thorntonbf]

This was my favorite part of the video, and I think it was genuine. The guy in the blue shirt and the one with grayer hair immediately afterward seemed like school kids seeing something amazing for the first time. I'm sure their day-to-day work is quite serious. Sometimes maybe it takes something simple to make you step back and realize that you really have some things in your life that are quite amazing.

[hudibras]

I might be cynical, but I think they were putting on a show a bit. They already had some sort of apparatus set up to do the simultaneous drops.

My guess is that it's a standard demonstration for visiting dignitaries and the like.

[jgrahamc]

Worth reading http://en.wikipedia.org/wiki/Equivalence_principle if you don't understand the last part.

[bjackman]

I guess this is a pretty superficial complaint, but this is a 2nd-generation clickbait-site link (posted on io9, reposted on thekidsshouldseethis.com). Why not post the Youtube link directly? This isn't really Hacker News material, anyway.

[norlowski]

Experiment, curiosity, huge NASA buildings, near vacuum. I'd rather read about this than mark zuckerberg.

[ghshephard]

A multi-story vacuum chamber on earth is pretty freaking amazing. Certainly stimulated my intellectual curiosity.

[teach]

Especially since the linked site is starting to hit resource limits. I had to refresh a few times before it would load.

Here's the youtube link: https://www.youtube.com/watch?v=E43-CfukEgs

[colinramsay]

> What to Submit

> If you had to reduce it to a sentence, the answer might be: anything that gratifies one's intellectual curiosity.

https://news.ycombinator.com/newsguidelines.html

[giarc]

Things that aren't HN material will be downvoted by members. This is currently sitting at #3, and therefore the HN community has determined that this is indeed HN material.

[cryowaffle]

Can someone explain to me the last part about the items standing still and no force acting on them? Isn't gravity acting on them, pulling the earth and items together?

[gradi3nt]

Imagine being inside of a closed box like an elevator. Without leaving the box there is no way to tell the difference from being in free fall towards Earth versus floating in interstellar space. Therefor, general relativity take the perspective that gravity is a fictitious force (like centrifugal force) that arises from the shape of spacetime.

[joshvm]

All the best facilities have big buttons labelled "Mega speed trigger".

But in seriousness, does the Moon not count? Surely space is the largest vacuum chamber we have access to!

[dia80]

I know how this will turn out but my intuition is screaming otherwise.

[derekp7]

One way of adjusting your intuition is to imagine the bowling ball and the feather standing still, and the ground coming up really fast and smacking them like a giant ping pong paddle. That's the only way I can get my eyes to agree with what the brain is thinking.

[saalweachter]

This is a great example of the 'Reality is Unrealistic' trope. The feathers just look so photoshopped falling next to the bowling ball, motionless, unfluttering.

[oneeyedpigeon]

I find it interesting that Brian Cox, the presenter and avowed scientist, obviously finds it so 'surprising' as well. Maybe that's the true meaning of being a scientist, though - he doesn't truly believe it until observing it with his own eyes.

[shittyanalogy]

Just imagine the air to be made up of a bunch of tiny physical balls. The bowling ball does a good job of getting them out of the way fast but the feather trips and stumbles on them as it makes it's way. With none of these tiny air balls in the way both objects move unimpeded until they hit the earth.

[t__r]

I find it a bit easier to understand if I imagine similar size and shape objects with a different weight. Say, a bunch of balls with equal radius but different weights. Does a near-zero-weight ball fall with a near-zero speed? Of course not. Etcetera.

[iterationx]

Yes, you already know the ending, but its worth watching just to see the massive structure.

[aaron695]

It interesting some people think a vacuum means a lot of pressure but really it's the same as 10 meters under water at sea level pressure.

[Cthulhu_]

^, explosive decompression in space also isn't as explosive as coming up from a few meters underwater in one go (it's from 1 to 0 atmospheres, instead of 100 to 1).

Not that I advocate explosive decompression in any circumstance, mind you.

[thearn4]

SPF is an awesome and unique facility, I wish more of the public would get to see it in person.

If you want to see more of it in video, it's also where the opening scene to "The Avengers" was filmed. Plum Brook Station has a whole collection of really cool (though mostly single-purpose) buildings.

[Animats]

If you want to see more of it in video, it's also where the opening scene to "The Avengers" was filmed.

It's appeared in a lot of movies, "Futureworld" (1973) being one of the first.

That's where the nuclear rocket upper stage for Apollo was supposed to be tested.

[italophil]

The space and aerospace programs of the sixties produced some really impressive technologies and facilities. Too bad government spending on technology research went down, just imagine what could be possible.

[frozenport]

From another perspective, these technologies left us with little science of utility (Tang?) while developing intercontinental ballistic missiles that loom over humanity like the Sword of Damocles. When historians from far off planets visit our nuclear wasteland they will see our thinly veiled space program as the beginning of end. :-)

[rglover]

Anybody else catch the NASA engineer wearing a SpaceX Dragon t-shirt? Nice.

[Marcus10110]

I'm wearing mine to Interstellar tonight!

[fdomig]

I love science. This is a very nice example of it.

[Shivetya]

I think my favorite part of this is not that they were able to demonstrate it so well but instead the reactions of people expecting it to actually occur.

[rajdevar]

I live in Ohio, Never knew that the biggest vacuum chamber is here until now.

[th0ma5]

Yup yup, it is NASA Plumbrook, the old reactor south of Sandusky. On the way to Cedar Point as a kid I was always in awe of the place as it was so big and you could only get within a few miles of it. My sixth grade teacher claimed a three eyed frog he had in a jar came from a nearby pond.

[Freestyler_3]

They could also have put a toy helicopter in there, just to add more fun.