iTopSpin

Please login or register.

Login with username, password and session length
Advanced search  

News:

Author Topic: Vortex Dome  (Read 504 times)

Jeremy McCreary

  • ITSA
  • Demigod member
  • **********
  • Posts: 3053
    • MOCpages
Vortex Dome
« 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.



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.

« Last Edit: April 29, 2021, 10:38:39 PM by Jeremy McCreary »
Logged
Playing with the physical world through LEGO

ta0

  • Administrator
  • Olympus member
  • *****
  • Posts: 12324
    • www.ta0.com
Re: Vortex Dome
« Reply #1 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 . . .
Logged

ortwin

  • Hero Member
  • *****
  • Posts: 394
Re: Vortex Dome
« Reply #2 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.

Logged

ta0

  • Administrator
  • Olympus member
  • *****
  • Posts: 12324
    • www.ta0.com
Re: Vortex Dome
« Reply #3 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
Logged

Jeremy McCreary

  • ITSA
  • Demigod member
  • **********
  • Posts: 3053
    • MOCpages
Re: Vortex Dome
« Reply #4 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.

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.
« Last Edit: April 30, 2021, 09:44:23 AM by Jeremy McCreary »
Logged

ortwin

  • Hero Member
  • *****
  • Posts: 394
Re: Vortex Dome
« Reply #5 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.


Logged

Jeremy McCreary

  • ITSA
  • Demigod member
  • **********
  • Posts: 3053
    • MOCpages
Re: Vortex Dome
« Reply #6 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.



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.
« Last Edit: April 30, 2021, 01:39:46 PM by Jeremy McCreary »
Logged

ortwin

  • Hero Member
  • *****
  • Posts: 394
Re: Vortex Dome
« Reply #7 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.
Logged

Jeremy McCreary

  • ITSA
  • Demigod member
  • **********
  • Posts: 3053
    • MOCpages
Re: Vortex Dome
« Reply #8 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.

« Last Edit: April 30, 2021, 02:31:25 PM by Jeremy McCreary »
Logged

ortwin

  • Hero Member
  • *****
  • Posts: 394
Re: Vortex Dome
« Reply #9 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. 
Logged

Jeremy McCreary

  • ITSA
  • Demigod member
  • **********
  • Posts: 3053
    • MOCpages
Re: Vortex Dome
« Reply #10 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.
« Last Edit: May 02, 2021, 11:08:57 AM by Jeremy McCreary »
Logged

ta0

  • Administrator
  • Olympus member
  • *****
  • Posts: 12324
    • www.ta0.com
Re: Vortex Dome
« Reply #11 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.
« Last Edit: May 02, 2021, 11:48:07 AM by ta0 »
Logged

ortwin

  • Hero Member
  • *****
  • Posts: 394
Re: Vortex Dome
« Reply #12 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.
Logged

ta0

  • Administrator
  • Olympus member
  • *****
  • Posts: 12324
    • www.ta0.com
Logged

Jeremy McCreary

  • ITSA
  • Demigod member
  • **********
  • Posts: 3053
    • MOCpages
Re: Vortex Dome
« Reply #14 on: May 02, 2021, 12:00:36 PM »

Love that name "kalliroscope"!

Interesting scientific article here.
Logged