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[Jeremy McCreary]

This new LEGO top combines 2 of my favorite gimmicks. The video is best viewed on a computer, as captions added on YouTube don't show up on mobile devices. Each segment shows the top with the freely swinging fluorescent parts in a different configuration. See the YouTube description for details.



This continues a series of fluorescent tops started in my Blacklight tops post.

Below are some older non-fluorescent centrifugal tops in visible light. No need to watch it through. The forebear of the top above comes in at 8:31.

[ta0]

I have only watched the first video so far, as they are pretty long.
The tops in black light are beautiful. And the video is very well done and relaxing.
Thanks for sharing.

[ta0]

I finally found my UV lamp and looked at some of my tops in both long wave (365 nm, UVA) and short wave (254 nm, UVC). I did not find any that would only fluoresce in short wave and not in long wave, but plenty of the reverse. This was a little surprising to me as UVC photons have more energy.

Here are some. The Upsys Downsys top was the most interesting:

Visible light


UVA


UVC

[Jeremy McCreary]

I have only watched the first video so far, as they are pretty long.
The tops in black light are beautiful. And the video is very well done and relaxing.
Thanks for sharing.

Thanks, ta0! I added the 2nd video mainly to show the top's predecessor spinning under visible light. It comes in at 8:31. The original post now makes that clear.

[Jeremy McCreary]

I finally found my UV lamp and looked at some of my tops in both long wave (365 nm, UVA) and short wave (254 nm, UVC). I did not find any that would only fluoresce in short wave and not in long wave, but plenty of the reverse. This was a little surprising to me as UVC photons have more energy.

Very useful data, ta0, as I was thinking about getting a shortwave UV source but was balking at the risk of UVB or UVC skin and eye exposure. My cheap longwave UVA (392 nm) party blacklights are billed as safe for prolonged exposure. Where did you get your 365 nm lamp?

Perhaps it's asking a lot of an organic pigment molecule to absorb a UVC photon and then shed most of that energy via strictly non-radiative transitions before spitting out a visible photon -- and to do so without any breaking bonds. Probably safer to disallow UVC absorption to begin with.

Does that top in the middle spin well?

[ta0]

The UV light I have (Raytech, model LS-7) is switchable between the two wavelengths. I got it to cure optical adhesive so it is powerful but they also have smaller models: www.raytechultraviolet.com

That Wizzzer top is discussed here: The Wackiest Top Ever Sold

[Jeremy McCreary]

Thanks, I'll give RayTech a look.

The 4 most strongly fluorescent LEGO colors are all translucent if not transparent at visible and long UVA wavelengths. Three of them appear below.



The fluorescent colors in the next tier down are much dimmer, and most are opaque. Since the majority of transparent LEGO parts show don't fluoresce at all, the polycarbonate used to make transparent parts contributes no fluorescence on its own.

In a 3D object with significant depth in the incoming UV direction, I'd imagine that visible+UV translucency would (i) allow the UV to excite more potential emitters, and (ii) allow more of the emitted visible light to reach the viewer. A translucent fluorescent throwing top might be pretty spectacular.