# Why 'h' for Planck's constant? **URL:** \ **Category:** Factual Questions\ **Created:** [May 26, 2010, 12:18am UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768 "2010-05-26T00:18:52Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![Derleth](https://avatars.discourse-cdn.com/v4/letter/d/b9e5f3/32.png) [@Derleth](https://boards.straightdope.com/u/Derleth)\ **Post date:** [March 9, 2012, 11:28pm UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/21 "2012-03-09T23:28:31Z")
> [@Chipacabra](#): > > You still use π?😉 I prefer [τ](http://tauday.com/). ---
**Author:** ![mathmore](https://avatars.discourse-cdn.com/v4/letter/m/f17d59/32.png) [@mathmore](https://boards.straightdope.com/u/mathmore)\ **Post date:** [September 2, 2017, 1:50am UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/22 "2017-09-02T01:50:35Z")
He chose h because it stands for “hilfe” in german, wich means “help me”. He included this constant within a theory that he did’nt belive, he was despairing. ---
**Author:** ![Itself](https://avatars.discourse-cdn.com/v4/letter/i/d07c76/32.png) [@Itself](https://boards.straightdope.com/u/Itself)\ **Post date:** [September 2, 2017, 2:17pm UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/23 "2017-09-02T14:17:48Z")
> [@John\_Mace](#): > > Real physicists use ħ, not h (“h-bar” = h/2π). 🆒 _Real_ real physicists just set _ħ_ = 1. ---
**Author:** ![IAmBroom](https://avatars.discourse-cdn.com/v4/letter/i/977dab/32.png) [@IAmBroom](https://boards.straightdope.com/u/IAmBroom)\ **Post date:** [September 2, 2017, 2:39pm UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/24 "2017-09-02T14:39:14Z")
> [@mathmore](#): > > He chose h because it stands for “hilfe” in german, wich means “help me”. He included this constant within a theory that he did’nt belive, he was despairing. That sounds like a “Just-So” story. Since we have citations from near the period supporting the “Hilfsgrösse”/“Auxiliary Variable” idea, it seems less likely. Can you support your claim with citations? ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [September 2, 2017, 4:07pm UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/25 "2017-09-02T16:07:20Z")
We need a science version of Poe’s Law. I first thought mathmore’s post was a joke, but I suppose it could be real. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 2, 2017, 5:02pm UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/26 "2017-09-02T17:02:04Z")
My guess is that someone told it to **mathmore** as a joke, but that he misinterpreted it as true, and rushed off to the Internet to share his newfound knowledge. ---
**Author:** ![Melbourne](https://avatars.discourse-cdn.com/v4/letter/m/b5e925/32.png) [@Melbourne](https://boards.straightdope.com/u/Melbourne)\ **Post date:** [September 2, 2017, 11:51pm UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/27 "2017-09-02T23:51:53Z")
> [@Chronos](#): > > My guess is that someone told it to **mathmore** as a joke, but that he misinterpreted it as true, and rushed off to the Internet to share his newfound knowledge. My guess is that **mathmore** told it as a joke, but that the SDMB misinterpreted it as as a ‘truth’, and rushed off to the Internet to share the accusation. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [September 3, 2017, 12:20am UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/28 "2017-09-03T00:20:25Z")
My guess is more consistent with the fact that he searched up a zombie thread to post it in. I mean, really, when was the last time you heard (or made up) a physics joke, and then searched online for some place to tell it? ---
**Author:** ![tim314](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim314/32/3468_2.png) [@tim314](https://boards.straightdope.com/u/tim314)\ **Post date:** [September 3, 2017, 1:20am UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/29 "2017-09-03T01:20:15Z")
> [@DHMO](#): > > it would be reasonable to conjecture that “h” represents the “harmonic oscillator”. I doubt this is it, only because Planck’s paper that introduced h doesn’t use the term “harmonic oscillators”. He instead used the term “linear monochromatic resonators”. He also said it in German, but either way none of those words start with an h. ---
**Author:** ![Chopsticks](https://avatars.discourse-cdn.com/v4/letter/c/cab0a1/32.png) [@Chopsticks](https://boards.straightdope.com/u/Chopsticks)\ **Post date:** [September 3, 2017, 4:17am UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/30 "2017-09-03T04:17:30Z")
> [@MikeS](#): > > [This paper](http://arxiv.org/pdf/physics/0402064) claims that Planck used _h_ for the German word _Hilfsgrösse_. My German is nicht sie gut, but as far as I can tell this means “auxiliary quantity”. If I saw ‘auxiliary quantity’ as a definition, the English phrase I’d use would be “fudge factor”. Which pairs well with Planck initially treating “quanta” as a math tool (vs a real object) ---
**Author:** ![tim314](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tim314/32/3468_2.png) [@tim314](https://boards.straightdope.com/u/tim314)\ **Post date:** [September 3, 2017, 6:46am UTC](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768/31 "2017-09-03T06:46:47Z")
> [@Pasta](#): > > Here’s my guess, backed up with absolutely no citations. > > Planck needed a symbol for a constant of proportionality, but _k_ was taken by Boltzmann’s constant (German: “konstant”). _h_ is nearby, distinct, and unused (contrast _i_ and _l_). I doubt it came from any particular word. Indeed, there was no good physical interpretation of _h_ when it was first written down. I’ve read somewhere that k wasn’t even used until Planck introduced it in the same paper where he introduced h. That is, Boltzmann had discussed the proportionality but not assigned the constant a letter nor attempted to compute its value. From [Planck’s Nobel lecture](https://www.nobelprize.org/nobel_prizes/physics/laureates/1918/planck-lecture.html): > [@Max Planck](#): > > This constant is often referred to as Boltzmann’s constant, although, to my knowledge, Boltzmann himself never introduced it - a peculiar state of affairs, which can be explained by the fact that Boltzmann, as appears from his occasional utterances, never gave thought to the possibility of carrying out an exact measurement of the constant. Nothing can better illustrate the positive and hectic pace of progress which the art of experimenters has made over the past twenty years, than the fact that since that time, not only one, but a great number of methods have been discovered for measuring the mass of a molecule with practically the same accuracy as that attained for a planet. [Previous page](https://boards.straightdope.com/t/why-h-for-plancks-constant/540768.md?page=1)