The heat from coffee or tea poured into this mug activates a powerful led light which is split by a tiny prism encased in the rim to project a wispy rainbow onto the escaping steam.
-- 2 fries shy of a happy meal, Jan 09 2022

Rainbow in steam over coffee https://www.reddit...._my_morning_coffee/
it's very faint in the photo, but I'm sure I've seen this effect. [Frankx, Jan 11 2022]

Hmm... you might run into issues using an LED (not enough of a "spread spectrum"). Use a good old-fashioned incandescent bulb.
-- neutrinos_shadow, Jan 09 2022


Sinse the steam is visible beacuse it is made of tiny water droplets, wouldn't it bow anyway? There's probably some obvious technical reason why not that I am to thick to think of this morning.
-- pocmloc, Jan 10 2022


Pastry deposited in haste, before someone thinks of a reason why this can't work. [+]
-- pertinax, Jan 10 2022


+ This would be pretty for drinking some rainbow tea!
-- xandram, Jan 10 2022


I like this. May I suggest that the source pot of coffee or tea be painted to be a 'Pot of Gold'?
-- AusCan531, Jan 11 2022


// Nope. Explaining why not requires a short science class (linked).//

According to Quora the number one answer to the question;
"Will white LED disperse into seven colours of rainbow when passed through a prism?"

is;

"Yes, of course it will. However (1) the intensity of the colors will not be as uniform as that with sunlight; (2) The color distribution seen may vary with manufacturer."

...

Now about deleting my annos from your postings... you got a stick up your ass?
-- 2 fries shy of a happy meal, Jan 11 2022


To create a real rainbow in your hot drink vapour you need (1) a bright light source offset slightly from your head, such that the line from your eyes to the mug to the light source is an angle of 42°, (2) cool air so that the vapour condenses and forms suspended droplets, and (3) dark background.

Suggested is to wear a voluminous matt black cape, and carry a walking stick, and wear hat-mounted lamp arm about 1m long which supports an incandescent light bulb with a parabolic reflector and shades to direct the light onto the cup which can be held at arms length in front of the cloak ( supported on the telescopic rail and tripod feet of the converted walking stick), which provides a dark background or viewing the resultant bow.

Alternatively build the kitchen or serving area such that the point where the drink consumer stands or sit is illuminated by a bright light from behind them and to one side (to create the 42° angle), while the area in front of them is dark and un-illuminated to give the required dark background. Climate control outlets can ensure that the counter-top is filled with cool, saturated and fairly still air to maximise vapour formation.
-- pocmloc, Jan 11 2022


//wear a voluminous matt black cape, and carry a walking stick, and wear hat-mounted lamp arm about 1m long which supports an incandescent light bulb//

Own that catwalk, [poc]!
-- pertinax, Jan 11 2022


Working out any possible kinks with this idea would be well worth it. What a great positive visual to start your day.
-- doctorremulac3, Jan 12 2022


// Working out any possible kinks with this idea would be well worth it. //

Some people's kinks is a stick up the ass. Luckily, [poc] has a walking stick, a stage, and a cape.
-- 4and20, Jan 12 2022


Uhh, okay.

Thinking a fan in the handle blowing the steam in a vortex using aimed holes outside the rim might give you a little steam tornado column that would catch the light more effectively.
-- doctorremulac3, Jan 12 2022


//you might run into issues using an LED (not enough of a "spread spectrum")//

This is a problem in the process of stopping being a problem, on account of a solution. The old white LEDs would be a mixture of chemistries, or of separate emitters clustered together in one housing. Since the development of blue and now UV LEDs we can just use various phosphors to tune the emission spectrum however you like.
-- bs0u0155, Jan 12 2022


I did some very half-baked experimenting this evening. Preliminary conclusions: very bright but small and shielded light source required. Very dark room required. Cold ambient temperature required. No rainbow spotted before a disembodied voice came from the other room: "is my tea ready yet? Why is the light off in the kitchen? Are you ok?"
-- pocmloc, Jan 12 2022


It's a start...
-- 2 fries shy of a happy meal, Jan 14 2022


//just use various phosphors to tune the emission spectrum//

Interesting; what do you mean by "various phosphors"?

Actually, don't worry; I looked it up.
-- pertinax, Jan 14 2022


My only question is, is there generally *enough* steam for this to work? [+]
-- 21 Quest, Jan 15 2022


I saw a rainbow projected on the steam of a mug one day on an imgur gif. Can't find it anymore, it was pretty cool and probably removed so some asshole like me wouldn't start a clock ticking. Oops. Tried for far longer than I should have to find it again for a link but no luck. It made me think that it should be able to recreated artificially.
-- 2 fries shy of a happy meal, Jan 15 2022


No
-- pocmloc, Jan 15 2022


[STEAMBOW]

...origins...

~Directed by M. Night Shayamalan~
-- 2 fries shy of a happy meal, Jan 15 2022


sp. Dark Night Shimmer-Dram
-- pertinax, Jan 15 2022


After noting that in weather forecasts "freezing fog" is a thing, I believe a warming rainbow, i.e., steambow is sure to be a hit. We have steam, why not use it to the utmost?
-- reensure, Jan 17 2022



random, halfbakery