Comments on: A hoopy frood

By: James

James — Fri, 17 Feb 2012 17:06:43 +0000

“Sure, just like actually going to the moon is easier and cheaper than faking it on a soundstage in Arizona . . .

j/k ”

How’s that a joke? Going to the moon for real IS easier than faking it. Rocket science is EASY.

By: Zhorik

Zhorik — Wed, 15 Feb 2012 05:49:24 +0000

Helen, I really enjoyed the video. If you make another video like this what I would love to see is to have a separate camera filming you at the same time from the outside and then do a split screen view with the synchronized hoop-centric and outside views.

-George

By: Zhorik

Zhorik — Wed, 15 Feb 2012 05:49:24 +0000

-George

By: Zhorik

Zhorik — Wed, 15 Feb 2012 05:49:23 +0000

-George

By: Pete Down Under

Pete Down Under — Tue, 14 Feb 2012 00:18:26 +0000

I really enjoyed Helen’s control over the hoop, particularly when changing hands, and moving from inside the hoop to outside. It looked so simple, so it had to have taken a hell of a lot of practice to make it look so “easy”!

Believe it or not, the hand control actually reminded me of learning the quarterstaff a few years ago. The hands have to be quick, precise, and firm, all at the same time, *and* know where to ‘expect’ the wood (hoop) to be.

I wonder if this unusual camera viewpoint would make a good training video?

By: Nigel Depledge

Nigel Depledge — Mon, 13 Feb 2012 13:18:44 +0000

Helen (46) said:

I don’t even understand Chris’ comment about it being fake- I have no idea what technology you would use to fake something like this, but strapping a small camera to a hoop seems to me to be a much easier and probably cheaper option!

Sure, just like actually going to the moon is easier and cheaper than faking it on a soundstage in Arizona . . .

j/k

By: Nigel Depledge

Nigel Depledge — Mon, 13 Feb 2012 13:04:52 +0000

James E (15) said:

From Roy Bishop’s “Orbital Motion” in the RASC Observer’s Handbook 2012:

In the case of orbits, the common misconception is that the inward gravitational
force is balanced by an outward “centrifugal force.” Newton’s view is simpler: There
is only one force, the inward pull of gravity. There is no physical agent to cause
an outward force. (Note that forces cause accelerations, not vice versa.) Also, if
there were an outward supporting force, the two forces would cancel and, as Galileo
realized, the body would then move along a straight line. If you choose a rotating
reference frame and then ignore the rotation (mistake no. 1), you have to pretend there
is a “centrifugal force” (mistake no. 2) in order to make sense of motions occurring
within this frame. The two mistakes effectively cancel, but the description has been
made needlessly complicated, and if you do not realize what you have done, you do
not understand the motion.

Nevertheless, denser particles will settle to the outer end of a centrifuge tube when it is spun.

Newton also stated that every action has an equal and opposite reaction.

Centrifugal “force” is the inertial reaction to centripetal acceleration.

By: Shawn Urban

Shawn Urban — Mon, 13 Feb 2012 08:49:57 +0000

I just read the comments and like the way Richard (comment 21) compared the apparent motion of the outside to the geocentric view of the Universe.

By: Shawn Urban

Shawn Urban — Mon, 13 Feb 2012 06:52:19 +0000

Hi Phil,

What struck me most about this video was how apparently disconnected and haphazard the movement of everything outside of the reference frame (camera view) was.

Throughout the video, I couldn’t help thinking how many observations we make of our Universe are just as confusing until we view them from the proper frame. What is so amazing is that we have the cognitive ability to study these observations and imagine different plausible frames until we understand the underlying science.

Shawn

By: Joreth

Joreth — Mon, 13 Feb 2012 05:01:50 +0000

For those who are complaining or confused by why she doesn’t just stand there & let it spin around her waist, who have never seen a hula hoop dancer, or think that hula hooping is all about super-fast spinning, I recommend watching this video of another hoop dancer who performed at Skepticon: http://www.youtube.com/watch?feature=player_embedded&v=59BP3HjjfIE

You’ll notice that for the majority of her hooping time, the hoop is actually spinning pretty slowly, and several times she spins along with the hoop, which also can account for some of the “slowness” that appears to be in the above video.

By: thew

thew — Sun, 12 Feb 2012 20:02:25 +0000

Phil said:
“But I wonder what other weird change-of-frames would benefit from using this camera technique? That might make a fun series of videos.”

I saw a video once from a camera mounted on the end of a sword, facing toward the hilt, so the blade and swordsman were in view, but they seem to have used an unlicensed song in the video and now it’s blocked.

By: Mike Torr

Mike Torr — Sun, 12 Feb 2012 19:51:48 +0000

Yay! @Helen – thanks for taking the time to drop by and explain all that, much appreciated. Love the video

By: Rogerio

Rogerio — Sun, 12 Feb 2012 19:50:41 +0000

one simple idea and a awesome effect

By: Kim

Kim — Sun, 12 Feb 2012 15:27:34 +0000

The hoop looks huge because she’s using a fisheye lens which distorts the edges. She also combined two videos, which is why she has two different outfits.

By: Helen

Helen — Sun, 12 Feb 2012 12:08:44 +0000

I made this video, and just happened to come across this article. I just wanted to say that it’s nice to hear some intelligent discussions going on and to read the scientific debate. I was just messing around with my camera, so it is fascinating to me to be confusing so many people!

When there is a larger portion of me inside the hoop (i.e. my waist) you’ll notice that my body fills the screen and momentarily blocks the view, and this happens about once every 3 seconds.
When you spin a hula hoop around your hand (a much smaller portion), you will notice that it takes a significantly longer amount of rotations for the hoop to get back to where it started.
When you are hoop dancing in actuality you can quite often have the same part of the hoop in your hand for a while, even though to the outside viewer it appears to be spinning pretty fast.

If you also pay attention to my grip, there are times when I am moving my body with the hoop, and actually holding on tightly to the hoop, rather than letting it spin round me. At these points of the dance I deliberately gripped the hoop opposite the camera so I would be in the frame, to give a more interesting perspective, and also because the balance of the hoop was off by having a camera attached to it!

And in respect to the slo-mo debate, parts 0.55-0.58 and 2.10-2.28 are slowed down to half the speed, the rest is in realtime. I wasn’t trying to mess with people’s heads, just make a cool film!

Special brownie points to Travis for nailing it on the head.
I don’t even understand Chris’ comment about it being fake- I have no idea what technology you would use to fake something like this, but strapping a small camera to a hoop seems to me to be a much easier and probably cheaper option!

By: Tom Callahan

Tom Callahan — Sun, 12 Feb 2012 06:27:47 +0000

Get out a slo-mo cam and I think you’ll find that the speed the hula hoop rotates around the body and the speed it rotates relative to itself are not the same thing. It swings around your hips pretty quickly but because it’s also “walking” along your body, the rate at which a specific point on it goes around is much slower. I noticed this once at a father-daughter dance where I had to embarrass myself badly in the hula-hoop competition. The hoops they had were junk and the one I had had duct tape holding the seam together. I noticed that the duct tape moved around a lot slower than I would have thought. Camera==duct tape in this case. Add in the wide-angle effect mentioned earlier in the comments and you have the effect as seen.

By: Wayne on the Plains

Wayne on the Plains — Sun, 12 Feb 2012 04:33:02 +0000

… not that I doubt Phil’s ability to point a teapot correctly.

By: Wayne on the Plains

Wayne on the Plains — Sun, 12 Feb 2012 04:31:54 +0000

Okay, I probably shouldn’t have tried to multitask reading the text while watching the video. I read “how to point a telescope” as “how to point a teapot” and got really confused for a second there…

By: slang

slang — Sun, 12 Feb 2012 02:03:16 +0000

Cute. But how was it done? Which camera?

By: JB of Brisbane

JB of Brisbane — Sat, 11 Feb 2012 10:23:55 +0000

@db26 – Of course it isn’t. Anyone can see it’s a camera with a hula hoop on it!

By: db26

db26 — Sat, 11 Feb 2012 07:07:08 +0000

If you thought that was a hula hoop with a camera on it, I’m afraid you are all morons.

By: Cathy

Cathy — Sat, 11 Feb 2012 05:39:55 +0000

You some some hoopy froods? Go to a rave and watch a hoop performer like this one using their full LED setup with tape for streaks. It’s preeeeeetyyyyy and you don’t need to actually take any drugs to get the awesome trippy patterns.

By: Stephanie

Stephanie — Sat, 11 Feb 2012 04:11:27 +0000

There’s also the 360 camera ball.

http://www.youtube.com/watch?v=Th5zlUe6gOE

By: HJ Hornbeck

HJ Hornbeck — Sat, 11 Feb 2012 02:59:13 +0000

I’d also like to point out that the fish-eye lens helps create the slow-motion effect; objects have to cross a wider angular arc to appear to move the same distance across the screen. Our field of view is roughly 90 degrees, so cropping the video down to half the original resolution and filling your eyeballs with it should be more accurate to what you’d see!

HJ Hornbeck
(PS. Yes, I tried it. Yes, I felt somewhat sick afterwards…)

By: MadScientist

MadScientist — Fri, 10 Feb 2012 23:05:35 +0000

I disagree that the motion is slower than expected – the motion would be related to the ratio of the hooper’s waist to the inner perimeter of the hoop. I would expect virtually everybody who’s played with a hoop to have noticed that. Spinning the hoop on a leg or wrist shows the comparative effect nicely.