UV light

Dix · 1413622. Thu Jun 23, 2022 9:07 am

I just posted this in Quite Interestings, then realised that it would fit well under U too.

Minerals that change colours when exposed to UV light.

https://www.utu.fi/en/news/press-release/natural-mineral-hackmanite-can-change-colour-almost-indefinitely-enabling

PDR · 1413623. Thu Jun 23, 2022 11:01 am

Or perhaps the V-series as UV radiation kills vampires...

:0)

PDR

ConorOberstIsGo · 1413640. Thu Jun 23, 2022 1:16 pm

1. UV (probably UVC rather than UVB or UVA) is the lowest-energy electromagnetic radiation that is considered to be ionising. This is important when discussing whether microwaves or 5G mobile phone masts can give you cancer, because if they could, then presumably so could visible light. But we don't see conspiracy theorists frightened of flashlights so we have to presume that they've never seen the electromagnetic spectrum diagram in my bathroom and in almost every science classroom in the modern world. If we _could_ ionise matter with longer wavelength radiation, the implications for the energy sector would be world-changing (wow!) but the implications for the nature of the physics would be universe-ending (aww!).

2. Doubtless a physics buff will correct me on some points but I'd also love to hear from a medical authority: Does the human body _need_ the same kind of UV light to synthesise vitamin D that can cause skin damage and cancer? If not, could we create a suncream that only blocked the harmful wavelengths? I am a pale and unhealthy man so have no idea whether you use cream if you want a tan or have to go without to bronze yourself in a 'natural' way.

Dix · 1413831. Sat Jun 25, 2022 12:48 pm

UV light plus the presence of liquid water seems also to be involved in creating the fresh pleasant smell of laundry dried outside in sunlight

(I think I posted about this earlier too, but I can't find the post)

Dix · 1421896. Mon Oct 31, 2022 1:17 pm

"Free lunch" for plants?

In winter, where there's less daylight available, you can boost plant growth by using a film that converts UV light to red light but is otherwise transparent.

It doesn't give you a free lunch, but it does give you 1.4 times more Swissh Chard in a couple of months.

Depending on how costly and/or how durable the film is, one would imagine that this might save some plant feed in greenhouses.