iTopSpin

NSTR => Non SpinTop Related => Topic started by: Jeremy McCreary on April 29, 2021, 10:34:59 PM

Title: Vortex Dome
Post by: Jeremy McCreary on April 29, 2021, 10:34:59 PM
My Vortex Dome arrived from the UK just a few days after ordering it from Amazon. The trippy wavy swirly patterns it makes are even better than I imagined from Tim's video. And it's not just a passive show. You have a hand in making them happen!

However, not so wild about the unadvertised fortune-telling function.

(https://i.ibb.co/SK83MfS/20210428-120527.jpg)

The feature makes some sense for a device that's basically part of a crystal ball with mica flakes and magnetic needles instead of tea leaves inside. Problem is, it has a Siri-like interface who insists on being addressed as Madam Xelda.

Her track record's not bad, but she has a mean streak. When I consulted her this morning, she couldn't stop laughing. When I asked her what was so funny, she said, "Oh man, wait till you see what happens to you next Friday!"

BTW, here's what it looks like when all the mica's settled. The short black lines are the magnetic needles.

(https://i.ibb.co/xLTKhfx/20210428-125434.jpg)
Title: Re: Vortex Dome
Post by: ta0 on April 29, 2021, 11:19:44 PM
Looks very nice! Congratulations!

I also wish that things didn't come with free unadvertised extras . . .  :P

Mm, Mistress von Karman and now Madam Xelda. I see some pattern here. I will pay more attention to your comments about Mrs. McCreary in the future . . .
Title: Re: Vortex Dome
Post by: ortwin on April 30, 2021, 03:15:15 AM
Nice!
Are those needles really magnets, or are they just some ferromagnetic material?
Can you rotate them by placing one of those stirring devices beneath that are usually used in chemistry/biology labs?
Take a picture for us  of the bottom side, I want to give you ideas for a tip.
As a stem something like this (https://pics.okluge.de/okluge/media/image/fb/19/80/xsyn-s21i00025_1.jpg).

Title: Re: Vortex Dome
Post by: ta0 on April 30, 2021, 09:02:23 AM
Can you rotate them by placing one of those stirring devices beneath that are usually used in chemistry/biology labs?
Take a picture for us  of the bottom side, I want to give you ideas for a tip.
Tim shows the bottom turntable and also how to stir the magnetic particles with a magnet:

https://www.youtube.com/watch?v=3ZHzDBEh-YA
Title: Re: Vortex Dome
Post by: Jeremy McCreary on April 30, 2021, 09:40:43 AM
Are those needles really magnets, or are they just some ferromagnetic material?
Can you rotate them by placing one of those stirring devices beneath that are usually used in chemistry/biology labs?

The needles tend to clump and align on their own, so they're magnetized to some extent. The small but strong supplied external magnet can grab and drag them around through either the clear dome or the stainless steel bottom.

Take a picture for us  of the bottom side, I want to give you ideas for a tip.
As a stem something like this (https://pics.okluge.de/okluge/media/image/fb/19/80/xsyn-s21i00025_1.jpg).

What we have here is a failure to communicate. There will be no effort to turn this prized possession into a top.

Even in a parallel universe where I were inclined to try, there would still be the matter of the slightly off-center rotating base.

Then there's this...

To do the experiment with a top, however, the mass of the top must be much larger than the mass of the liquid or the liquid will make the spin unstable and also dampen it very fast.

ta0 speaks truth.
Title: Re: Vortex Dome
Post by: ortwin on April 30, 2021, 12:04:56 PM

To do the experiment with a top, however, the mass of the top must be much larger than the mass of the liquid or the liquid will make the spin unstable and also dampen it very fast.

ta0 speaks truth.
He is right but you could build a heavy flywheel around it.
Come on give me the details, can the rotating base be disassembled to get rid of it?I won't force you to do it, but maybe I get one and do it.


Title: Re: Vortex Dome
Post by: Jeremy McCreary on April 30, 2021, 01:33:05 PM
...can the rotating base be disassembled to get rid of it?
...maybe I get one and do it.

(https://i.ibb.co/zsZz8V4/20210430-112028.jpg)

I see no non-destructive way to remove the rotating base. The bottom half of the central aluminum cylinder rotates WRT to the top half, which is somehow fixed to the stainless plate. Both connections are hidden.
Title: Re: Vortex Dome
Post by: ortwin on April 30, 2021, 01:49:29 PM
Thank you Jeremy for the picture and the explanation. So maybe not a good idea to get rid of the base, blocking its rotation with a screw or something might work.
Title: Re: Vortex Dome
Post by: Jeremy McCreary on April 30, 2021, 02:26:28 PM
Thank you Jeremy for the picture and the explanation. So maybe not a good idea to get rid of the base, blocking its rotation with a screw or something might work.

You're welcome.

If you really want to block base rotation, I'd recommend an adhesive-based solution, as you probably don't want to be poking holes in that circular steel plate. Near as I can tell, the blue fluid is sealed in a clear glass tank resting on and keyed to this plate.

Alternatively, you could make a detachable "top adapter" that just slides over the existing aluminum turntable. The turntable is 49.5 mm in diameter and 15 mm high. Perhaps something like the add-on you were considering for your Spartan.

The stainless plate could just sit on the top adapter. As long as you get the fluid tank up to operating speed, doesn't matter much what else is allowed to rotate.

Title: Re: Vortex Dome
Post by: ortwin on May 02, 2021, 08:30:07 AM
You say that is mica inside? What solvent? Do you know where I could get that stuff? I've had an idea  for a while now,  not spinning top related, where I could make good use of that optical effect it produces. 
Title: Re: Vortex Dome
Post by: Jeremy McCreary on May 02, 2021, 11:04:03 AM
You say that is mica inside? What solvent? Do you know where I could get that stuff? I've had an idea  for a while now,  not spinning top related, where I could make good use of that optical effect it produces.

Yes, not sure, and no, resp. I get the impression that the fluid has roughly the viscosity of water. Doesn't seem to be non-Newtonian, so could well be just colored water.
Title: Re: Vortex Dome
Post by: ta0 on May 02, 2021, 11:42:09 AM
These instructions say colored water:
https://makezine.com/projects/rheoscopic-coffee-table/

The Wikipedia description rheoscopic fluid says:
Quote
Rheoscopic fluid means "current showing" fluid. Such liquids are effective in visualizing dynamic currents in fluids, such as convection and laminar flow. They are microscopic crystalline platelets such as mica, metallic flakes, or fish scales in suspension in a fluid such as water or glycol stearate.

And:
Quote
Kalliroscope is an art device/technique based on rheoscopic fluids invented by artist Paul Matisse.


From a comment on youtube:
Quote
For those interested, you can make your own rheoscopic fluid with very fine mica powder...   it’s sold in a variety of different forms (cosmetics, abrasives etc) but they’re all the same, it’s the particle size that matters and the smaller the better...   because of the variety of uses, just look for the cheapest solution of the smallest particles.
Title: Re: Vortex Dome
Post by: ortwin on May 02, 2021, 11:50:27 AM
Thank you ta0! You pointed me to a valuable source for my project.
I was thinking about visualizing magnetohydrodynamic flows.
Title: Re: Vortex Dome
Post by: ta0 on May 02, 2021, 11:51:52 AM
Two good videos:

https://www.youtube.com/watch?v=5TGFqoZiM1U

https://www.youtube.com/watch?v=TpJq9g5DkCA
Title: Re: Vortex Dome
Post by: Jeremy McCreary on May 02, 2021, 12:00:36 PM
Love that name "kalliroscope"!

Interesting scientific article here (https://arxiv.org/abs/1806.06120).
Title: Re: Vortex Dome
Post by: ortwin on May 02, 2021, 02:22:03 PM
Thank you Jeremy and ta0 for the research you did and for the valuable results you came up with. That puts some pressure on me though as to soon present something I made from that.....  I guess that is a good thing.
It is not a big secret, since I said "magnetohydrodynamic" it is probably obvious to you that eventually I want to make something like that table where also some  electrodes are incorporated that can be moved from the outside and some strong magnets that provide the magnetic field to achieve the effect. If it is mica the stuff should not interact itself directly to too a large an extend with the magnetic or electric field.


EDIT: Something in principle like this (https://www.evilmadscientist.com/2006/mhd-i-demonstrate-magnetohydrodynamic-propulsion-in-a-minute/) but the rheoscopic fluid should replace the pepper.
Title: Re: Vortex Dome
Post by: ortwin on May 17, 2021, 05:49:09 AM
In the meantime I prepared my rheoscopic fluid.
The receipt in that article that Jeremy pointed me to, works great and is so simple. One part shaving cream from a can and 20 parts (by weight) of water.
Even without food coloring it looks great in the bottle!

Another idea what to do with the stuff, is to make a base for endurance tops!
You know it can be very boring to watch those tops: The first two minutes after the start,  when there is still something happening (precession, dance...)are fine. Also the last few minutes when you hope it will get past a certain time mark. But those ten (or hopefully soon more) minutes in between are plain boring!If one would have something like that vortex dome to play with while time passes that would be great. I am thinking of two concave glasses inside each other, the sealing as a spacer of about 3mm. The space in between filled with the rheoscopic fluid. Some pieces of ferromagnetic material also inside to allow for "magnetic play".




Title: Re: Vortex Dome
Post by: Jeremy McCreary on May 17, 2021, 08:58:53 AM
Good to know that the shaving cream works. Bought the cream and am now scheming to do some tank experiments with tops that I won't mind cleaning up afterward.

Looking forward to seeing your rheoscopic top base. Since you'll be adding magnetic particles, might be interesting to see if you can also get a (non-endurance) top with magnets to stir the fluid as it spins. I realize that any coupling between the top and the fluid will add yet another resistance, so this would have to be an alternative way to play with the base.
Title: Re: Vortex Dome
Post by: ortwin on May 17, 2021, 09:10:28 AM
..., might be interesting to see if you can also get a (non-endurance) top with magnets to stir the fluid as it spins.
Very good idea, I will try!
Title: Re: Vortex Dome
Post by: ortwin on May 28, 2021, 05:34:25 AM
Beta version of the "Rheoscopic Base" (speaking about quick and dirty)
https://youtu.be/H_2CjRNV16w (https://youtu.be/H_2CjRNV16w)

Possible improvements:

- add food coloring to the fluid
- use glue instead of the clamps
- ...
 
@Jeremy: Your idea with the magnet in the top to stir the fluid did not work well up to now. It only couples and stirs when directly under the top, which means the effect of the stirring is hardly visible since this top does not travel a lot. Maybe I should try a LEGO top with that "traveling tip" added.

 
Title: Re: Vortex Dome
Post by: Jeremy McCreary on May 28, 2021, 06:28:01 AM
Very promising!

If I were giving out Nobel Prizes, the inventors of Swiss Army knives, Velcro, binder clips, burritos, and "Yes, dear" would all have them -- the last for the Peace Prize.
Title: Re: Vortex Dome
Post by: ortwin on May 28, 2021, 09:38:26 AM
Placing that base on top of a  cup of hot water, makes a nice display of convection cells. 


(https://i.ibb.co/s2zHKKJ/convection-cells.jpg) (https://ibb.co/s2zHKKJ)
Title: Re: Vortex Dome
Post by: Jeremy McCreary on May 28, 2021, 11:12:30 AM
Wow! Definitely trying that with mine.
Title: Re: Vortex Dome
Post by: ta0 on May 29, 2021, 10:14:43 AM
Very nice! Perhaps one day I build one. But my dream has always being to build a cloud chamber (cosmic ray detector). Perhaps I could combine the two  ???