# Avogadro's Number? Name That Constant! **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [August 1, 2003, 5:41pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404 "2003-08-01T17:41:54Z")\ **Posts on this page:** 13\ **Page:** 2
**Author:** ![Beryl\_Mooncalf\_1](https://avatars.discourse-cdn.com/v4/letter/b/9f8e36/32.png) [@Beryl\_Mooncalf\_1](https://boards.straightdope.com/u/Beryl_Mooncalf_1)\ **Post date:** [August 2, 2003, 10:17am UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/21 "2003-08-02T10:17:44Z")
So what number is this? ``` sq. rt. -9 ``` ---
**Author:** ![MC\_Master\_of\_Ceremonies](https://avatars.discourse-cdn.com/v4/letter/m/bb73d2/32.png) [@MC\_Master\_of\_Ceremonies](https://boards.straightdope.com/u/MC_Master_of_Ceremonies)\ **Post date:** [August 2, 2003, 12:06pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/22 "2003-08-02T12:06:27Z")
> [@](#): > > \*Originally posted by Beryl\_Mooncalf \* > \*\*So what number is this? > > ``` > sq. rt. -9 ** > > ``` 3i ---
**Author:** ![bonzer](https://avatars.discourse-cdn.com/v4/letter/b/45deac/32.png) [@bonzer](https://boards.straightdope.com/u/bonzer)\ **Post date:** [August 2, 2003, 12:08pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/23 "2003-08-02T12:08:25Z")
> [@](#): > > \*Originally posted by kambuckta \* > Bugger THAT…who the hell is _Avogadro_, and why does he have the privilege of a number next to his name? [A brief biography with portrait.](http://www.mcallister.com/vacuum.html) > [@](#): > > **AVOGADRO’S LAW** , a statement that under the same conditions of temperature and pressure, equal volumes of different gasses contain an equal number of molecules. This was highly non-obvious. After all, given a 1 litre bottle of pure helium gas and a 1 litre bottle of argon, you wouldn’t necessarily guess that both have the same number of atoms in them. Particularly since an argon atom is about ten times heavier than a helium one, and larger as well. Perhaps there are billions upon billions more atoms in one bottle than the other. But, in fact, they do have the same number in them. Avogadro’s Law basically says that similar bottles of gases always have the same number of molecules in them. (In the particular case of helium and argon, a molecule is just a single atom.) If you know that a 1 litre bottle of gas always has the same number of molecules in it, that number’s a useful way of thinking about how many atoms there are. Technically, the number of molecules in a cubic centimeter of gas at a defined temperature and pressure is called _Loschmidt’s number_ and it’s such that the number of them in that 1 litre bottle is 2.69 x 10[sup]22[/sup]. _Avogadro’s number_ is closely related to this and works out as 6.022 x 10[sup]23[/sup]. The exact definition is a bit technical, but the underlying idea is the same. It’s important because a physicist or chemist looking at an everyday object and wondering how many atoms are in it will think “it’ll be roughly 10[sup]23[/sup] or so” as their first rough guess. Not 1000 or a Googol (1 followed by a 100 zeros). About Avogadro’s number of them. Avogadro gets to have his name associated with the number because he was really the first to realise that there was such a single number that could be used in this way, though he didn’t know its numerical value. [Odd way to lose my Pit virginity …] ---
**Author:** ![JustPlainBryan](https://avatars.discourse-cdn.com/v4/letter/j/57b2e6/32.png) [@JustPlainBryan](https://boards.straightdope.com/u/JustPlainBryan)\ **Post date:** [August 2, 2003, 5:12pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/24 "2003-08-02T17:12:33Z")
I thought everyone knew what Avocado’s number is. It’s the number of avocados you can pile onto a burger before it tips over. That number is 4.5. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 2, 2003, 10:40pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/25 "2003-08-02T22:40:07Z")
> [@](#): > > \*Originally posted by Chefguy \* > \*\ ***I** like pi on a planck. \*\* …pi…on a planck…c’mon, this is good stuff… ---
**Author:** ![Michael\_Ellis](https://avatars.discourse-cdn.com/v4/letter/m/977dab/32.png) [@Michael\_Ellis](https://boards.straightdope.com/u/Michael_Ellis)\ **Post date:** [August 2, 2003, 10:43pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/26 "2003-08-02T22:43:17Z")
> [@](#): > > \*Originally posted by CzechMaster401k \* > **The point of the 6.02x10^23 is just used because it’s an extremely large number in addition to being a number that every ninth-grade science student knows.** Bingo. ---
**Author:** ![MC\_Master\_of\_Ceremonies](https://avatars.discourse-cdn.com/v4/letter/m/bb73d2/32.png) [@MC\_Master\_of\_Ceremonies](https://boards.straightdope.com/u/MC_Master_of_Ceremonies)\ **Post date:** [August 2, 2003, 10:46pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/27 "2003-08-02T22:46:57Z")
> [@](#): > > \*Originally posted by Chefguy \* > \*\*…pi…on a planck…c’mon, this is good stuff… \*\* When I’m in the h-bar I like to have a Planck on two pi(es). ---
**Author:** ![Larry\_Griffin-Kentzel](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/larry_griffin-kentzel/32/14787_2.png) [@Larry\_Griffin-Kentzel](https://boards.straightdope.com/u/Larry_Griffin-Kentzel)\ **Post date:** [August 2, 2003, 11:07pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/28 "2003-08-02T23:07:17Z")
**culture** , I’m going to assume that you meant to start this thread in [**MPSIMS**](http://boards.straightdope.com/sdmb/forumdisplay.php?s=&forumid=4). I’ll move it for you. * * * **Cajun Man** ~ SDMB Moderator ---
**Author:** ![Chavardz](https://avatars.discourse-cdn.com/v4/letter/c/91b2a8/32.png) [@Chavardz](https://boards.straightdope.com/u/Chavardz)\ **Post date:** [August 2, 2003, 11:27pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/29 "2003-08-02T23:27:40Z")
The problem with constants is that they’re really only ther to solve problems mathmatecians couldn’t solve and most of them aren’t terribly precise. The only good thing about them is that they work (jeez, talk about fighting two sides of an issue). As an engineer I’ve learned to appreciate them but not love them. ---
**Author:** ![Plankspanker](https://avatars.discourse-cdn.com/v4/letter/p/6a8cbe/32.png) [@Plankspanker](https://boards.straightdope.com/u/Plankspanker)\ **Post date:** [August 3, 2003, 9:56pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/30 "2003-08-03T21:56:31Z")
slight hijack here, but i must put forward my ‘all theoretical physicists are dirty old men’ theory. otherwise, why else would quarks have names like naked, bottom, and charm? or maybe i’m just being dumb… :rolleyes: incidentally, i like my pi on a planck, but i prefer it with philedelphia to quark. please stop me if i’m bohring you to death 😃 (sorry, i couldnt stop. they made me do it!) ---
**Author:** ![MC\_Master\_of\_Ceremonies](https://avatars.discourse-cdn.com/v4/letter/m/bb73d2/32.png) [@MC\_Master\_of\_Ceremonies](https://boards.straightdope.com/u/MC_Master_of_Ceremonies)\ **Post date:** [August 3, 2003, 10:32pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/31 "2003-08-03T22:32:55Z")
There’s no such thing as a naked quark (actually I’m guesing a ‘naked’ quark is a reference to quark confinement, but it’s the first time I’ve heard them called ‘naked’), quarks, unlike the other fermions, are very prudish. ---
**Author:** ![Chefguy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chefguy/32/138_2.png) [@Chefguy](https://boards.straightdope.com/u/Chefguy)\ **Post date:** [August 3, 2003, 11:47pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/32 "2003-08-03T23:47:26Z")
> [@](#): > > \*Originally posted by Plankspanker \* > \*\*slight hijack here, but i must put forward my ‘all theoretical physicists are dirty old men’ theory. otherwise, why else would quarks have names like naked, bottom, and charm? > > or maybe i’m just being dumb… :rolleyes: > > incidentally, i like my pi on a planck, but i prefer it with philedelphia to quark. please stop me if i’m bohring you to death 😃 (sorry, i couldnt stop. they made me do it!) \*\* And a cup of Maxwell house…mmmmmm ---
**Author:** ![culture](https://avatars.discourse-cdn.com/v4/letter/c/958977/32.png) [@culture](https://boards.straightdope.com/u/culture)\ **Post date:** [August 4, 2003, 1:50pm UTC](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404/33 "2003-08-04T13:50:06Z")
> [@](#): > > \*Originally posted by Cajun Man \* > \*\ ***culture** , I’m going to assume that you meant to start this thread in [**MPSIMS**](http://boards.straightdope.com/sdmb/forumdisplay.php?s=&forumid=4). I’ll move it for you. > > * * * > > **Cajun Man** ~ SDMB Moderator \*\* Dang. Now I can’t curse the opposition in my post! Anyway, you’all got them all. I guess that is no suprise. [Previous page](https://boards.straightdope.com/t/avogadros-number-name-that-constant/192404.md?page=1)