How much is a joule?
Bob
My friend's mother's heart had to be zapped with 300 joules
yesterday to get it back into a normal rythm (she had heart
surgery last week).
My friend was curious as to how much energy a joule is, but the
only definations I could find (in terms of # of electrons, coulombs,
etc.) were of no help to her (or me).
Is there a relationship of joules to watts or something else that
us lay people can relate to?
Thanks kindly,
Bob Park
Chuck Hanavin
Well, 1 watt is 1 joule per second. So if she was zapped
for 1 second, it would be roughly 300 watts of power.
I hope that helps.
--
Chuck Hanavin Email: han...@eecis.udel.edu
Senior Electronics Specialist Phone: 302-831-8403
140 Evan Hall, University of Delaware Callsign: WB3FJJ
Newark, Delaware 19716
Mike Beyers
: Is there a relationship of joules to watts or something else that
The joule is a basic unit of energy. It is 1 kg-m /s.
A 16 lb bowling ball falling 14 feet would have 300 joules of energy.
16lbs = 7.3kg (we'll assume a lb is 2.2kg here, i.e. a measure of mass).
14ft = 4.3 meters
2
and gravity is a force of 9.8m/s
so 7.3kg x 9.8 m/s2 x 4.3 m = (about) 300 kg m2/s2 or 300 joules.
Its lots of energy, in terms of either electricity of bowling balls.
( So did I mess up on my physics 101? Its been a long time.)
--
Thanks,
Mike
Prabal Dutta
>yesterday to get it back into a normal rythm (she had heart
>surgery last week).
>My friend was curious as to how much energy a joule is, but the
>us lay people can relate to?
energy = force * distance
and force = mass * acceleration
substituting, we get:
energy = mass * acceleration * distance
Let's put in some numbers"
300 J = 55 kg * 9.8 m/s^2 * distance
Solving for distance, we have:
distance = .557 meters = 21.7 inches
So, assuming your friend's mother weighs 121 lbs, 300 Joules would
be the energy required to lift her about 22 inches off the ground.
Hope this helps.
- Prabal
--
--
James E. Thompson
: substituting, we get:
: Hope this helps.
: - Prabal
: --
: --
Jeez, why do things have to get so complex ???
------------>> 1 joule = 1 watt-sec <<--------------------
...Jim Thompson
% James E.Thompson, P.E. Consulting Engineer % mens %
% Analog/Mixed-Signal ASIC's and Discrete Systems % et %
% Phoenix, Arizona Voice: (602)460-2350 % manus %
% ana...@primenet.com Fax: (602)460-2142 % Brass Rat 1962 %
Steve Kreckman
>surgery last week).
>My friend was curious as to how much energy a joule is, but the
>etc.) were of no help to her (or me).
A joule (J) is defined as: 1kg m^2 sec^-2
A watt is : 1kg m^2 sec^-3 or J sec^1 or J/sec
so...a watt is a certain amount of joules over time. You'd have to know
how long the charge was delivered to convert to watts.
Cheers,
Steve
--
Steve Kreckman (kr...@ix.netcom.com)
- Whoever called it 'near-beer' was a poor judge of distance
Frank Reid
megajoule.
--
Frank re...@indiana.edu
Benjamin P. Carter
>A joule is a watt-second. A stick of dynamite releases approximately one
>megajoule.
Another familiar unit of energy is the kilowatt-hour, which is
1 KWH = (1000 watts) (3600 seconds) = 3.6 megajoules.
--
Ben Carter internet address: b...@netcom.com
Gerald Evans
> <snip>
> Is there a relationship of joules to watts or something else that
> us lay people can relate to?
> Bob Park
A joule is a measure of ENERGY whereas a watt is a measure of POWER.
Power is the measure of the _rate_ of energy use/flow (etc)...
a watt is equal to a joule per second. So a 100W lightbulb uses up
100J each second, for example.
In everyday units, a joule is 0.23885 calories. Most nutritional
information on food items gives the energy value of the food in
Calories [NB. a Calorie=1000 calories, this being a case where
the capital letter does make a difference!].
Hence 300 Joules is 0.072 Calories, which is probably about the
amount of energy in a grain or two of sugar!
--Dan Evans.
(Using someone else's a/c atm).
(Email via gev...@cafe.glassnet.com until 12 April, then to my usual address:
dan....@sjc.ox.ac.uk).
Alan Wilson
:
: My friend's mother's heart had to be zapped with 300 joules
: surgery last week).
:
: My friend was curious as to how much energy a joule is, but the
: only definations I could find (in terms of # of electrons, coulombs,
: etc.) were of no help to her (or me).
: Is there a relationship of joules to watts or something else that
:
: Thanks kindly,
capacitor is 1/2 CV^2. This is often used in expressing the energy
available from a photoflash gun. A 300 Joule (or 300 watt-second) flash
gun is a moderate sized studio flash-- Many of the larger consumer-type
strobes are 25 joules.
For a spectacular demonstration, get some large 300 or 400 volt caps;
charge them up; and then short them with a screwdriver. This will take
the end off the screwdriver to say the least.
Have fun
Alan
:
Michael H Procter
>yesterday to get it back into a normal rythm (she had heart
>surgery last week).
>My friend was curious as to how much energy a joule is,
OK, a joule is a measure of energy, or work. To get a feeling for how much
it is, it is roughly equal to the amount of work done raising an apple by a
metre (ie picking an apple from the floor and putting it on a table).
Or you can look at it the other way round, it is the amount of energy given
up when an apple drops one metre. 300J is about the energy released if you
were to drop 6 bags of sugar from the 1st floor window in your house. (I
assume a bag of sugar is 1 kilogramme, and that the 1st floor window is above
the ground floor window which is above the ground.)
Other people have related it to watts. A Watt is how fast you are doing work,
one joule per second. So, 300J is the energy released by a 60W lightbulb in
5 seconds.
Hopefully, this will give you an intuitive guide to how much 300J is.
Have fun, and I hope your friend's mother recovers quickly.
Michael
--
M.Pr...@physics.oxford.ac.uk <-| | Help! I am being victimised by entropy!
Michael...@worc.ox.ac.uk <-| |------------------------------------------
procter....@ph.ox.ac.uk <-| | Factoid: 33550336 is a perfect number.
wo9...@sable.ox.ac.uk <-- One of these should work! Or a good guess...
richard steven walz
In article <3m3368$o...@ixnews1.ix.netcom.com > kr...@ix.netcom.com
(Steve Kreckman) writes:
> >My friend's mother's heart had to be zapped with 300 joules
> >yesterday to get it back into a normal rythm (she had heart
> >surgery last week).
>
> >only definations I could find (in terms of # of electrons, coulombs,
> >etc.) were of no help to her (or me).
>
>A watt is : 1kg m^2 sec^-3 or J sec^1 or J/sec
>
>so...a watt is a certain amount of joules over time. You'd have to know
>how long the charge was delivered to convert to watts.
-----------------------------------------------
Well, yes, but I think you left out the most useful (to the questioner)
answer; namely that a Joule is a Watt-second. Thus 300 Joules is 300
Watt-seconds, or about like getting as much as a 1000 Watt bulb or a hair
dryer for about 1/4 of a second. If she didn't have a cardiac arrest then
what she had was a planned intervention called cardioversion, to correct a
persistent arrythmia that traumatized heart tissue sometimes manifests and
which is not as efficient a rhythm and so is not as healthy. The current
varies, of course, with the resistance of the skin, which is highly
non-linear at those kinds of voltages ramping up and down. The charge is
stored in a capacitor or bank of several large dielectric can capacitors
and is released about as fast as the patient's resistance permits at a given
instant. The capacity is adjustable by dialing in Joules on a display.
-Steve Walz rst...@armory.com
Rodney MacLean
> Michael H Procter (pro...@teaching.physics.ox.ac.uk) wrote:
>
> : (I assume a bag of sugar is 1 kilogramme, and that the 1st floor window
> : is above : the ground floor window which is above the ground.)
>
> Bad assumption. In the U.S., sugar is sold in 5-pound bags, which makes
> a bag of sugar 2.27 kilograms.
>
> Does it strike anyone else as strange that England doesn't use English
> Weight Units, while the U.S. does?
>
> Harry C.
It stikes me strange that anyone would use a screwed up system like the
Imperial system. You know the system where there are miles and then there are
other miles, and there are pounds, and then there are other pounds.
How many links are there in a chain anyway?
Rodney MacLean
John Lundgren
John Lundgren
John Lundgren
Chris Matthaei
>Michael H Procter (pro...@teaching.physics.ox.ac.uk) wrote:
>: (I assume a bag of sugar is 1 kilogramme, and that the 1st floor window
>: is above : the ground floor window which is above the ground.)
If the 1st floor is above the ground floor which is above the ground, wouldn't
that make it the 2nd floor?
>Bad assumption. In the U.S., sugar is sold in 5-pound bags, which makes
>a bag of sugar 2.27 kilograms.
>Does it strike anyone else as strange that England doesn't use English
>Weight Units, while the U.S. does?
Yeah, and they say 1st floor when they actually mean 2nd floor. :)
BTW. We always used metric in chemistry and physics class. But to say that
a car goes 300 km/hr or that someone weighs 75 kg doesn't mean much to me.
For everyday things I just convert to English units.
just another ignorant American,
Chris
Jim Potter
table releases 4 joules when it hits the floor. The energy of a 4000 lb automobile
traveling at 60 mph is 654,000 joules. A 100 watt light bulb burning for 3 seconds
is 300 joules.
--
===================================================================
James M. Potter, President Internet: jp...@roadrunner.com
JP Accelerator Works, Inc. AOL: jp...@aol.com,jpo...@aol.com
2245 47th Street Voice: 505-662-5804
Los Alamos, NM 87544-1604 FAX: 505-662-5210
Dan Hariton x5596
1 joule (joule=energy) is the energy of 1 watt power (watt=power)
dissipated continously for one second (second=time).
1 joule = ( 1 volt X 1 ampere ) X 1 second = 1 watt X 1 second
dan
Harry H Conover
: 1 joule = 1 watt X 1 second
: 1 joule (joule=energy) is the energy of 1 watt power (watt=power)
: dissipated continously for one second (second=time).
: 1 joule = ( 1 volt X 1 ampere ) X 1 second = 1 watt X 1 second
: dan
So, how many bowling ball feet is that, and if his grandmother was
healthy enough to go bowling, why did they have to give her a
300 Joule (ouch) jump-start?
I'm confused.
:-)
Harry C.
Mike H.
On 10 Apr 1995 01:29:42 GMT, in <3ma1m6$b...@sundog.tiac.net>
con...@max.tiac.net (Harry H Conover) wrote.....
> Does it strike anyone else as strange that England doesn't use English
> Weight Units, while the U.S. does?
>
Well we do and we don't! Officially we are all metric. Unofficially most
people deal and think in imperial - lbs, ins, oz etc.
Personally, I use both. Imperial for real life and metric for anything
scientific.
----------------------------------------------------------------------------
Mike H. (Software Sans Frontieres) PGP:818C97EB75366540 8A27D2AB8E7482CB
Umail 1.50 from ftp.demon.co.uk:/pub/ibmpc/umail,/pub/ibmpc/windows/umail
----------------------------------------------------------------------------
Harry H Conover
: (I assume a bag of sugar is 1 kilogramme, and that the 1st floor window
: is above : the ground floor window which is above the ground.)
Bad assumption. In the U.S., sugar is sold in 5-pound bags, which makes
a bag of sugar 2.27 kilograms.
Does it strike anyone else as strange that England doesn't use English
Weight Units, while the U.S. does?
Harry C.
Le Cleac'h Jean-michel
>
> As far as screwed up, well it made sense, at least a much sense
>as the measurement of a meter. Something like one ten millionth
>the distance from Paris to the North Pole, or something like that.
>
the french Parliament born from the revolution instituted the metric
system (the father of the I.S. system), it was to give to humanity
(and not only to the french people) a system of units in which everyone
can trust without any regional or national peculiarities. The principle
was to base the units on natural and therefore universal phenomenons.
The meter is not as you say a fraction of the distance between Paris
and the pole but the ten millionth of the quarter of the Earth meridian
(no reference to a peculiar meridian).
Today the philosophy is the same and one meter is the distance travelled
by the ligth in vacuum in a fraction (see your encyclopedia) of second.
Best regards
Jean-Michel Le Cleac'h, Paris, France
Walter Gray
>
>On 10 Apr 1995 01:29:42 GMT, in <3ma1m6$b...@sundog.tiac.net>
> con...@max.tiac.net (Harry H Conover) wrote.....
>
>> Weight Units, while the U.S. does?
>>
>people deal and think in imperial - lbs, ins, oz etc.
>
>Personally, I use both. Imperial for real life and metric for anything
>scientific.
>
The US doesn't really use the English system, they have their own 'short'
versions of things like tons, gallons, etc. That's why everything seems
bigger in the US of A :)
- - - - - - - - - - - - - - disclaimers - - - - - - - - - - - - - - -
davis...@bvc.edu
After Einstein and his brilliant theory of relativity we need to use a
simple conversion to determine units of the nuclear binding energy (E) in
E=mc^2. Therefore 1 J = 1 kg m^2/s^2.
Since this information doesn't pertain to anyone in this newsgroup it
may be a simple piece to keep in the back of your mind in case you are
quizzed on your nuclear chemistry knowledge.
Dick Kaulfuss
:
: On 10 Apr 1995 01:29:42 GMT, in <3ma1m6$b...@sundog.tiac.net>
: con...@max.tiac.net (Harry H Conover) wrote.....
: > Does it strike anyone else as strange that England doesn't use English
: > Weight Units, while the U.S. does?
: >
: Well we do and we don't! Officially we are all metric. Unofficially most
: people deal and think in imperial - lbs, ins, oz etc.
I think you'll find that the up-and-coming generation are almost totally
metricated. My two teenage sons have only vague notions of what pounds
and ounces, and inches, feet and yards are about. They are much more at
home with kilograms and metres.
: Personally, I use both. Imperial for real life and metric for anything
: scientific.
Me too! Especially with things like carpets, which come in metric
widths, but are priced by the square yard!
Dick
David P Norwood
: db...@ripco.com (Dave Baiocchi) writes:
: > John Lundgren (jlun...@delta1.deltanet.com) wrote:
: >
: > I'm no physics major, but I'm pretty sure that a joule is a Newton-meter.
: Certainly . . . but I think the original poster was looking for something
: a little more along the lines of a physical example to get a feel of how
: much 1 J is.
: Here's one: Take an apple (m ~ 0.1 kg) and lift it above the ground a
: distance of 1 m. You've now just put 1 J [= (0.1 kg)(10 m/s^2)(1 m)] of
: potential energy into the apple.
: Or, equivalently, the amount of energy released as sound, heat,
: deformation of the apple and/or ground, etc., by dropping an apple from
: a height of 1 m is 1 J.
Or lift a dollars worth of nickels and put them in your pocket.
dave
Erich Mueller
: I've take the high road here for one major reason: I'm an electrical engineer,
: and EEs have always been metric. And it has nothing to do with the wisdom of
I whole-heartedly agree, but say brother are crt sizes, wire gauges,
magnetic media- or electronic component sizes and God allmighty knows
what else metric in the 'land of the free...'?
: the French government. It has more to do with the folks who developed the
: discipline. Good for them.
: Lastly, as my ramble draws to a close, I'd like to make some observations. The
: first is that you actually have to be certifiably insane to use imperial,
: English, or American measure if you don't have to. Quick: what's the volume of
Well we here in ol'Germany have to use them imperial sized, but advertize
them with SI figures which looks even more dumb that way believe me!
(e.g. five and a quarter inch disk advertized as 13.335 cm!!!!)
: a gallon of water at standard temp and press in cubic feet? MKS and CGS are
: boring in comparison, but do have a sensible set of interrelationships.
: Uh-oh, that guy wasn't an American, was he?... 8-)
: Bob
: (who's not had enough coffee yet this AM, or maybe too much...)
: R. C. Lacovara, Ph. D.
: Electrical Engineer in Computer Science drag...
: GeoControl Systems voice: 713 333 2561
: Suite 100 fax: 713 333 2966
: 1720 NASA Road 1
: Houston, Texas 77058
regards Erich
--
Erich Mueller, Jahnstr 27, 64285 Darmstadt, Germany Tel: +49-6151-661523
Privat: e...@gonzales.swb.de e...@vchem.swb.de Fax: +49-6151-662045
Dienst: emueller%esoc....@vm.gmd.de XADC-MISCON Tel: +49-6151-902640
--------------------- METEOSAT MISSION CONTROL -------------------------
Erich Mueller
: And the "Inch" is defined as 2.54 meters
This is hecto "Inch" or did you forget a centi in front of the meters?
: by the suede Mott Johansson when they
: delivered a measuresystem to Ford
: /oo
: Sweden
skoll
rick...@ids.net
>: : A joule is a watt-second. A stick of dynamite releases approximately one
>: : megajoule.
>: : --
>: : Frank re...@indiana.edu
>
>
You know, I'm tired of reading these messages. I know that this is probably an
old thread, hey, I haven't read this group in awhile. But surely, someone must
know the exact number of electrons in a joule? I was told in school the other
day, but have forgotten, but I seem to remember it was a 6 followed by a
helluvalot of zeros..<G>
-rIck-
Harry H Conover
: You know, I'm tired of reading these messages. I know that this is probably an
: old thread, hey, I haven't read this group in awhile. But surely, someone must
: know the exact number of electrons in a joule? I was told in school the other
: day, but have forgotten, but I seem to remember it was a 6 followed by a
: helluvalot of zeros..<G>
: -rIck-
Rick, I don't mean to sound sarcastic, but if you believe that a Joule
in any way relates to a certain number of electronics, you need to read
these threads a little more closely than most people! :-)
Should I assume that you're trying to crank a little humor into the
thread, or that you don't know the difference between units of energy and
charge (Joules vs. Coulombs)?
Harry C.
John Henry Hazelton
1/1 = 1
Joule = Watt/Second or Amp/Second at 1ohm at 1volt
1/1 = 1
David Burton
> In Article <D6yIr...@rci.ripco.com>
> db...@ripco.com (Dave Baiocchi) writes:
. . .
> >I'm no physics major, but I'm pretty sure that a joule is a Newton-meter.
>
> You know, I'm tired of reading these messages. I know that this is probably a
> old thread, hey, I haven't read this group in awhile. But surely, someone mus
> know the exact number of electrons in a joule?
Yes, though (of course) the number of electrons in a jewel depends
upon its size (in carats) and what gemstone it is. The canonical
gemstone used for counting electrons is the 1 carat diamond, which
contains 6.0167 x 10**22 electrons. That number is called a jewel.
> I was told in school the other
> day, but have forgotten, but I seem to remember it was a 6 followed by a
> helluvalot of zeros..<G>
Yes, the number of electrons in a standard jewel (a 1 carat diamond)
is 6 followed by a helluvalot of zeros (22 of them). However,
you're probably thinking of the number of electrons in a *mole*,
rather than a jewel.
Of course, just as a cubit depends upon the size of your arm, the
actual number of electrons in a mole depends upon what species of
mole (there are a lot of species in the family Talpidae), and also
whether it is a baby mole or a full-grown, adult mole.
Fortunately, there is a standard for the weight of a "canonical"
adult mole. It is actually about 1/20 the weight of an adult North
American Common Mole. I don't know why it is so small. Perhaps
the "standard" weight is supposed to be that of a baby shrew mole or
something, or maybe the physicists who came up with the unit didn't
bother to check how big moles really grow. My guess is that naming
the unit after the rodent was a whimsical choice, and they really
didn't care much whether or not their "standard" rodent was a
midget.
Anyhow, the "standard" mole has another problem, besides his small
stature. He is 100% water! (That's actually a pretty good
approximation to real moles, a lot closer than the weight, anyhow.)
His composition was chosen for easy analysis. Anyhow, the standard
mole is a hypothetical 100% H2O critter that contains exactly
avocado's number of electrons (and the same number of protons, of
course).
I'll bet that's the number you are thinking of: "6 followed by a
helluvalot of zeros" (23 of 'em, to be exact). It is called
avocado's number, which is the number of electrons in a 10 carat
diamond. Legend has it that it is called avocado's number because
an 18th century Italian scientist (named Amedeo) exclaimed, upon
seeing a 10 carat diamond, "Wow! That's the size of an avocado!"
He was exaggerating, of course, but nevertheless the term stuck.
For some reason, a mole is now more commonly used than a jewel.
Why use a unit based upon a 10 carat diamond instead of a 1 carat
diamond? Who knows? You could ask the same question about
optical wavelength measurements: why are we all using nanometers
these days, instead of angstroms? (A nanometer is 10 angstroms.)
Anyhow, back to moles. Unfortunately, as a result of improved
measurement techniques, the original "avocado's number,"
6.0225x10**23, which was believed to be the number of electrons in a
10 carat diamond, is now known to have been slightly high. There
are actually only 6.0167x10**23 electrons in a 10 carat diamond.
That's very close, of course (less than .01% off). Unfortunately,
the entire metric weight system is based upon the old value of
avocado's number!
Oops! Rather than change the whole weight system, it was decided to
stick with the original number, and accept the fact that a 10 carat
diamond doesn't have quite enough electrons in it. (So we're
getting gypped by almost .01% every time we buy diamond jewelry by
the carat!)
Anyhow, avocado's number is still officially 6.0225x10**23, even
though that is *actually* the number of electrons in a 10.0096 carat
diamond, rather than in a 10 carat diamond.
(It is all the fault of the traces of carbon 14 in the diamond,
actually, which slightly increases the weight, and thereby decreases
the number of molecules per given weight. avocado's number is
actually the number of electrons in a hypothetical 10 carat diamond
made entirely of carbon-12.)
You now have enough almost enough information to calculate the
weight of that hypothetical, standardized, 100% H2O rodent, the
"mole." That poor, soggy creature is defined to contain avocado's
number of electrons (and protons). Recall that carbon-12 contains 6
electrons, 6 protons, and 6 neutrons per atom. Oxygen-16 contains 8
electrons, 8 protons, and 8 neutrons per atom. Hydrogen contains
just one proton and one electron per atom.
So, can you now figure out what the canonical mole weighs?
Okay, I won't keep you guessing. Here's how you can figure it out
(very closely, anyhow). Water is H2O, so it contains 10 electrons,
10 protons, and 8 neutrons per molecule (two hydrogens and an
oxygen). A proton and a neutron weigh (almost exactly) the same,
and an electrons weighs almost nothing, so water is 10/(10+8) =
10/18 = 55.555% protons and 44.444% neutrons. Carbon is only 50%
protons (6 protons and 6 neutrons). So, one water mole is therefore
50/50.5555 jewels, or 0.9 jewels, or 9.0 carats. A carat is 1/5
gram, so that means the "standard" family Talpidae rodent weighs
9/5 = 1.8 grams. (Actually, a typical adult North American mole
actually weighs more like 1.8 *ounces*, not grams, but don't blame
me, I didn't create the standard.)
So, now you know: to several digits of precision, a mole has
avocado's number of electrons in 1.8 grams of water, which is the
same number of electrons as a 10 carat diamond. (Avocado is
sometimes misspelled avogadro - maybe that is avocado in some
other language?)
P.S. - I don't even like avocados! (Nor moles, for that matter.)
(But I'd be happy to take off your hands any extra 10 carat diamonds
that you might have laying around!)
-Dave Burton <dbu...@burtonsys.com> or <dbu...@salzo.cary.nc.us>
alternate: <dbu...@ios.com> or <dbu...@cybernetics.net>
David Burton
(was: How many electrons in a joule?)
dbu...@salzo.Cary.NC.US (David Burton) writes:
> . . . So, one water mole therefore weighs
> 50/50.5555 jewels, or 0.9 jewels, or 9.0 carats. A carat is 1/5 . . .
^ ^^^^^^ ^^^
Oops! Good grief, look at all the mistakes. I very thoroughly
scrambled that sentence. How embarassing! I should have said:
So, one water mole therefore weighs 50/55.55 of what a 10 carat
diamond weighs, like 0.9 moles = 9.0 jewels weighing 9.0 carats.
A carat is 1/5 . . .
Here's a corrected article.
Also, I've added some additional information the end about a related
term, the "coulomb" (a/k/a "cool ohm"), which is yet another (much
smaller) unit of measurement for counting electrons.
_______________________________________________________________________________
rick...@ids.net writes:
. .
> You know, I'm tired of reading these messages. I know that this is probably a
> old thread, hey, I haven't read this group in awhile. But surely, someone mus
> know the exact number of electrons in a joule?
Yes, though (of course) the number of electrons in a jewel depends
upon its size (in carats) and what gemstone it is. The canonical
gemstone used for counting electrons is the 1 carat diamond, which
contains 6.0167 x 10**22 electrons. That number is called a jewel.
> I was told in school the other
> day, but have forgotten, but I seem to remember it was a 6 followed by a
> helluvalot of zeros..<G>
Yes, the number of electrons in a standard jewel (a 1 carat diamond)
is 6 followed by a helluvalot of zeros (22 of them). However,
you're probably thinking of the number of electrons in a *mole*,
rather than a jewel.
Of course, just as a cubit depends upon the size of your arm, the
actual number of electrons in a mole depends upon the species of
(It is all the fault of the traces of carbon-14 in the diamond,
actually, which slightly increases the weight, and thereby decreases
the number of molecules per given weight. Avocado's number is
actually the number of electrons in a hypothetical 10 carat diamond
made entirely of carbon-12.)
You now have enough almost enough information to calculate the
weight of that hypothetical, standardized, 100% H2O rodent, the
"mole." That poor, soggy creature is defined to contain avocado's
number of electrons (and protons). Recall that carbon-12 contains
6 electrons, 6 protons, and 6 neutrons per atom. Oxygen-16 contains
8 electrons, 8 protons, and 8 neutrons per atom. Hydrogen contains
just one proton and one electron per atom.
So, can you now figure out what the canonical mole weighs?
Okay, I won't keep you guessing. Here's how you can figure it out
(very closely, anyhow). Water is H2O, so it contains 10 electrons,
10 protons, and 8 neutrons per molecule (two hydrogens and an
oxygen). A proton and a neutron weigh (almost exactly) the same,
and an electron weighs almost nothing, so water is 10/(10+8) = 10/18
= 55.55% protons and 44.44% neutrons. Carbon is only 50% protons
(6 protons and 6 neutrons). So, one water mole therefore weighs
50/55.55 of what a 10 carat diamond weighs, like 0.9 moles = 9.0
jewels weighing 9.0 carats. A carat is 1/5 gram, so that means
the "standard" family Talpidae rodent weighs 9/5 = 1.8 grams.
(Actually, a typical adult North American mole weighs more like
1.8 *ounces*, not grams, but don't blame me, I didn't create the
standard.)
So, now you know: to several digits of precision, a mole has
avocado's number of electrons in 1.8 grams of water, which is the
same number of electrons as a 10 carat diamond. (Avocado is
sometimes misspelled avogadro - maybe that is avocado in some
other language?)
A related term is the "coulomb," which is yet another (much smaller)
unit of measurement for counting electrons.
You might think that the term coulomb (pronounced like, and derived
from, "cool ohm") has something to do with electrical resistance
("ohms"). It doesn't. It was defined as the amount by which a one-
carat diamond is undersized. That is, it was defined as the number
of electrons by which a one-carat diamond is short of having 1/10
avocado's number of electrons.
(Well, as luck would have it, that's not really *quite* right any
more. That's what it was intended to be, but with ever-more-up-
to-date measurements, the exact number of electrons in a 10 carat
diamond (i.e., what *should* be avocado's number) got corrected
*again*, after the coulomb was defined. So, a coulomb is really
just a smidgen *over* the actual number of electrons by which
a one-carat diamond is short of having 1/10 avocado's number of
electrons. To be precise, a coulomb is defined as 6.2418x10**18
electrons, so the difference between a real 1-carat diamond and
a theoretical 1-carat diamond made entirely of carbon-12 is
(6.0225-6.0167)x10**22 electrons / 6.2418x10**18 electrons/coulomb
= 0.93 coulombs.)
Anyhow, the term "cool ohm" was apparently coined from "ice"
(slang for diamonds) and "Mho" (a unit of hardness based on the
diamond; the hardness of a diamond is defined to be 10 Mhos).
So, a one-carat diamond was said to have just "one cool ohm" short
of a full jewel (1/10 mole) of electrons (i.e., just a smidgen).
Okay, so how much smaller is a coulomb than a jewel, or a mole?
A mole is (6.0225x10**23 electrons/mole) / (6.2418x10**18
electrons/coulomb) = 96,487 coulombs/mole.
A jewel is (6.0167x10**22 electrons/jewel) / (6.2418x10**18
electrons/coulomb) = 9639.4 coulombs/jewel.
So, if high-grade diamonds cost $2500/carat, then that one cool
ohm difference between the size of a one-carat diamond and a
diamond containing a full jewel (1/10 mole) of electrons is worth
$2500/9639.4 = about a quarter (actually 25.9 cents).
--------------------------------------------------------------------------------
Richard Steven Walz
Thank you thank you thank you thank you thank you, for clearing all THAT
up! I don't think I have ROLF'd that hard in several years, and I think
that I might have hacked up a lung, but I don't know what lung tastes like!
Thanks for that, Dave, truly a net "classic" FAQ!!;->
-Steve Walz rst...@armory.com "another bastard of physics degree!"