Candle Flame Oscillations as a Clock (opens in new tab)

I was today years old when I learned that the frequency of a flicker candle flame is ~9.9Hz :-)

Very cool. I've always wondered what the shape of a flame is and how one could use physics to derive it. anyone have any leads for this?

While visiting a friend in Russia I was perplexed by the candle in his flat - it had zero flicker, was stable and unmoving. Eventually I learned how they heated the flat, with water flowing through pipes and heat radiation - so little to no air movement.

In the late 1980s I did an electrical engineering internship in a coal-fired power station over summer vacation. The gas furnace igniters ran continuously, but how do you detect presence or absence of burner flames against semi-apocalyptic background of ignited pulverised coal dust being air-blasted into the furnace? Have a little window and photosensor pointing at the burner flame and FFT. No spectral component spike at xHz (IIRC x ~= 13? -- it's a burner flame, underlying dynamics not same as for candle wick) --> ringing alarms, flashing lights.

> as it mainly depends on gravity and diameter of the flame

So cannot be used on a ship. Bummer.

Our sea-faring ancestors wouldn't be happy with this clock.

> Todays candles have been optimized for millenia not to flicker.

Where can I learn more about that? My google fu is failing me.

I want to know the precision of that clock!

My mind is blown candles flicker at a fixed rate

Are we absolutely sure we're not in "the matrix" ?

From the article:

> A fascinating fact is that the oscillation frequency is rather stable at ~9.9Hz as it mainly depends on gravity and diameter of the flame.

This reminds me of when I first heard about Dolbear's law by which you can get an approximate measurement of the air temperature using the number of chirps per minute from a cricket.

https://en.wikipedia.org/wiki/Dolbear%27s_law

Only tangentially related:

In the Quake source code, they have strings to represent the intensity over time of a flickering light source:

https://github.com/id-Software/Quake/blob/bf4ac424ce754894ac...

  // 3 CANDLE (first variety)
  lightstyle(3, "mmmmmaaaaammmmmaaaaaabcdefgabcdefg");

They range from a to z and progress through the string with time, so the candle starts out at medium "m" intensity for a bit before it goes dark ("a") for some time, etc.

I have recently become quite fascinated with how much of what we use daily relies on the laws of physics always working the exact same way. This is a wonderful example of that.

I love this. This is why we need science: a very interesting and curious fact is examined. Experiments are done and a toy is built based on the findings. It is all totally useless, excepts that human knowledge is brought forward and it is also fun. This is important. It is the reason why we are here. Life would be dull without these kind of highlights in my day. And for this, public funding is needed, because it makes people happy, and happiness is an important persuable goal of many public bodies. And because goal directed research (which is often dull and predictable) of stuff that can be financially exploited is funded anyway, non-publically.

Very interesting article from the same guy where he reverse engineers the randomness of a flicker LED.

https://cpldcpu.com/2013/12/08/hacking-a-candleflicker-led/

> Now, it’s a curious thing that we try to emulate the imperfections of candles. After all, candle makers have worked for centuries (and millennia) on optimizing candles NOT to flicker?

This reminds me of teenage me circa 1990 exploring electric guitar distortion and having an interesting conversation w/ my dad, who'd done a pretty serious paper on eliminating audio distortion as part of his CSEE degree from MIT.

The beginning of an alternative-universe candle computer that could've been used in the past.

What a wonderfully hacky project!

Noob question: How were the diagrams created?