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Author Topic: Curious Tippe Top behavior (more!)  (Read 6253 times)

ta0

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Curious Tippe Top behavior (more!)
« on: September 24, 2011, 12:53:23 AM »

The Tippe Top or Flip-over top is one of the most curious tops ever. But the other day playing with a cheap party giveaway Pablo brought home I noticed an even more curious thing: the top not only flipped over, but was "undecided", oscillating up and down several times before it finally did the flip.  Here is a litte video:

http://www.ta0.com/science/videos/tippe-top_undecided.swf

As you can see, it oscillates 5 times before flipping!   :o ???

This tippe top has a somewhat special construction, with an axle that protrudes at the bottom. This axle normally supports an internal star that slides down when the top flips but I had to take it out to obtain the oscillating effect. Actually, the reason I started to experiment with it was because it surprised me that the pointy tip would not stop it from flipping.

However, after some experimentation with several tops I found this behavior may happen with any tippe top if it is unbalanced.  By the way, mounting putty is also useful in unbalancing tops  >:D

One tippe top I tried was a nice and large (2.7 inch diameter) wooden flip over from the Burlington Top Museum catalog that has a handle to start it. I had always wanted to reproduce a picture that appeared in Scientific American showing the trace of the contact point as it moves around the body during the flip. Because this top is heavy it was easy to obtain by just spinning it on a sheet of carbon paper.  Here is the result:



A surprise for me was that the spiral trace did several turns around the top while the one on the article does less than a turn, before switching directions when the top is horizontal (where the trace forms a U).  I am not completely sure why the trace is not continuous (neither on mine, nor on the article picture where it was spun a glass coated with carbon.) It may be just something to do with the interaction with the carbon paper or it may be that the top has some bouncing off the surface as I read somewhere. A neat thing is that I can now tell that the person who spun the other top is probably left handed  8)
« Last Edit: September 24, 2011, 09:46:33 AM by ta0 »
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poptop

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Re: Curious Tippe Top behavior (more!)
« Reply #1 on: September 24, 2011, 11:35:47 AM »

The carbon paper trick is a neat way on convincing folks the top changes direction.  I love the u-turn!  I've had friends argue in disbelief when I told them this was the case.

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By the way, mounting putty is also useful in unbalancing tops 

FWIW, you can work on your top balancing skills by using "unbalancing putty".  Stick small blobs of putty on a well balanced top to get a feel for how much putty it takes to create some severity of vibration.  The same amount of putty should be about right to cure a vibe in an unbalanced top with similar vibe.
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Erratic Wobbler

ta0

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Re: Curious Tippe Top behavior (more!)
« Reply #2 on: September 24, 2011, 04:07:10 PM »

Yes, the U-turn happens when the top is horizontal and coincides with the spin around its stem changing direction (i.e., when it is zero!) However, I don't know if the U turn will convince them that the spin (with respect to the top) reverses. The direction in which the point of contact slips around the trace and the direction in which the top spins are not (at least to me) intuitively connected.  By the way, the center of the U points in the direction the top was originally spun.

I think the best way to convince somebody of the reverse of direction is to draw an arrow on the top.

I also tried it with a metal tippe top on carbon paper:



Here is the photo, by a certain Frank Johnson, reproduced in Scientific American:



It would be extremely cool if somebody used a very high speed camera to film the reversal of a tippe top (with reference markings on the body.)
« Last Edit: September 24, 2011, 11:06:37 PM by ta0 »
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johnm

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Re: Curious Tippe Top behavior (more!)
« Reply #3 on: September 24, 2011, 07:47:46 PM »

Interesting, if you balance the top with the protruding tip does it still flip?  If so I wonder how long the protrusion must be before it is too much.  Remember the top Philippee made which nicely flips with a little external assistance.

I am not completely sure why the trace is not continuous (neither on mine, nor on the article picture where it was spun a glass coated with carbon.) It may be just something to do with the interaction with the carbon paper or it may be that the top has some bouncing off the surface as I read somewhere.

Bouncing sounds right to me.  Have you tried spinning it on the carbon paper flipped over so it makes the trace on a piece of paper under the carbon paper.  Usually these tops travel in the process of flipping over and a skipping line on the paper would suggest some jumping from the surface.  We've spun other tops on paper like this to draw interesting paths and found that the unbalanced tops skip along the surface (thus the chattering sound)
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ta0

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Re: Curious Tippe Top behavior (more!)
« Reply #4 on: September 24, 2011, 11:56:29 PM »

Quote
Interesting, if you balance the top with the protruding tip does it still flip?  If so I wonder how long the protrusion must be before it is too much.  Remember the top Philippee made which nicely flips with a little external assistance.
When he top appears balanced it does a smooth, continues flip. Your question got me thinking. I don't see any way a balanced top could flip if it is spinning on a protruding tip. What must be happening is that in the effort to give it lots of spin I start the top at an angle large enough for the body to skim the surface.

Amazingly, there is a US patent for a tippe top with a little tip that can be pushed in and out. The idea of the inventor was to create a joker top: you show your victim how, when you spin it, it flips and then you give him/her the top to try it. But by a sleight of hand (well, a twist or push in the stem) you make a tip protrude thus making it an non-flippable top. All well in theory, but now I wonder if the inventor actually tried it. I also wonder if there would be a market for it . . .

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Bouncing sounds right to me.  Have you tried spinning it on the carbon paper flipped over so it makes the trace on a piece of paper under the carbon paper.  Usually these tops travel in the process of flipping over and a skipping line on the paper would suggest some jumping from the surface.  We've spun other tops on paper like this to draw interesting paths and found that the unbalanced tops skip along the surface (thus the chattering sound)
Thanks for the suggestion. I just did a quick try and in fact I got a skipping trace on the paper. So it must be true that the top does little bounces off the surface. Therefore the elasticity at the contact is important and the exact explanation of what happens is complicated as hell . . .
« Last Edit: September 25, 2011, 12:00:28 AM by ta0 »
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silvertop

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Re: Curious Tippe Top behavior (more!)
« Reply #5 on: September 25, 2011, 12:02:17 AM »

I have high speed film of one of my flipover tops taken by Andrew Davidhazy at RIT here in Rochester.  I'll have to look for it.  I was amazed to find that the top reversed direction of spin as well as flipping over.  Of course, the flipping over is the part that amazes folks most since the spin reversal is pretty much invisible in the real time world. ( I remain amazed to this day  that for  the filming, I actually cut two flipovers of different color in half vertically, and glued two halves back together to make the action more visible - with much gnashing of teeth as I tried to carefully sand the two halves to be perfect!  It was years later  that I realized I could have just painted the two halves of an intact top differently!)
 
I did find a fairly good film of a flipover / tippe top on U-tube - the relevant a action starts at :40 and ends at about 4:00 --- the top falls off the table at this point, but the film continues for another 2 minutes!

Tippe top

Additional note.  With regard to the plastic flipover with the moveable point/stem in Tao's video, the point retracts as the top is set down spinning, making it just like a regular round ended flipover. It pops back out when the top reverses onto the end of the stem.  That oscillation behavior was always to be avoided at all costs as I tried to make 99.9% of my flipovers work properly.
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Don Olney
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silvertop

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Re: Curious Tippe Top behavior (more!)
« Reply #6 on: September 25, 2011, 12:10:10 AM »

I found a link I had saved to another high speed video of a flipover..... I think this might be a segment of the film of my top.  It is a very low quality conversion!
http://www.teachertube.com/viewVideo.php?video_id=24249
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ta0

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Re: Curious Tippe Top behavior (more!)
« Reply #7 on: September 25, 2011, 09:16:37 AM »

Thanks for retrieving the videos, Don.  And I would love to see that video by the Rochester Institute of Technology (the city of Rochester is well known for its optical expertise: years ago I visited the Eastman museum and the laser fusion facility at the University of Rochester).

Unfortunately, the low quality version on teachertube is unusable:  there are two fake inversion of the spin (one in the first couple of seconds) due to a strobe effect (probably because of a compression that decreased the frame rate)! The spin around the vertical axis should not reverse.

The first video is pretty good. I love the jumping at the end of the flip.  I now realize it is very difficult to follow the inversion of the spin with respect to the top axis. But more markings on the top could help.

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With regard to the plastic flipover with the moveable point/stem in Tao's video, the point retracts as the top is set down spinning, making it just like a regular round ended flipover. It pops back out when the top reverses onto the end of the stem.

No, the tip on this top does not retract. Actually, it is what kept the two halves together. Now that I have opened it many times and it is worn I need to add some putty to keep it in place.

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That oscillation behavior was always to be avoided at all costs as I tried to make 99.9% of my flipovers work properly
I personally love that oscillation, it makes it even more mysterious.
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Jeremy McCreary

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Re: Curious Tippe Top behavior (more!)
« Reply #8 on: December 05, 2018, 01:18:13 PM »

I did find a fairly good film of a flipover / tippe top on U-tube - the relevant a action starts at :40 and ends at about 4:00 --- the top falls off the table at this point, but the film continues for another 2 minutes!

Apparently shot in the days before video editing, but a great demo of the motion nonetheless. And a testament to the conservation of angular momentum.
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Playing with the physical world through LEGO