 ot all students of freshman
physics will smile. Most will groan at what was
merely an adolescent pun...
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1
erg = 1 dyne-centimeter
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Over the decades since its first
appearance on that blackboard, other renditions have
come along -- none, it seems, with the illustration. The
following example was recently found on the web:
"Before its passing, the
dyne-centimeter said, 'Erg'," wrote Douglas Quebbeman
in a chat-room, adding, "As puns go, that wasn't much
of a joule, was it?"
Indeed it was not. To be literal, an erg
is exactly one hundred-millionth of a joule, and
yet the erg deserves respect alongside the joule.
Here's why...
| The erg is a unit of
work in the metric system. It denotes a
force (dyne) applied through a distance
(centimeter). Work is the
highest
form of energy and is entitled to its
own unit-of-measure. As you may be
persuaded to agree, erg is quite a
good candidate for the work assignment,
starting with...
...the word "centimeter" in
the solution, which, of course, is not
the creature you saw sketched on that blackboard.
When Americans ever get around to adopting
the metric system, they will need to get
used to such things as "first and 914 centimeters
to go" and "a miss is as good as 1.6 kilometers."
Now, the word "dyne" in the pun...
...was coined in 1873, from
the German use of Greek dynamis
"power," also inflected by French dyne.
However, the dyne is a unit of force
not power. Specifically, a dyne
is defined as "the force required to
accelerate a mass of one gram at a
rate of one centimeter per second
squared." Let us keep in mind,
the word "gram" denotes...
...a unit of mass not
weight. An object with a mass of one gram
will have a weight determined by the
gravitational field in which it is
weighed. One gram weighs zero
in earth orbit and -- oh, right, about one dyne
on the launch pad, where a kilogram
weighs 1,000 dynes or about 2 pounds
(abbreviated "lb", from an origin in the
Latin expression libra pondo, which
refers to the balance scale, but I
digress). A pound...
...is the non-metric unit-of
measure for force not mass, although
a balance scale measures either. The
non-metric unit-of-measure for mass is slug,
which might be cartoonable on a
blackboard. There is no
unit-of-measure for work other than foot-pound
or pound-foot, which has a funny
plural pound-feet.
| At this point I am
tempted beyond my powers to resist
and offer the following coinage: the
word "ugh" as a unit of work. Thus,
from now on, the world has 1 ugh
= 1 pound-foot. Come
on! The word "ugh" is no less
scientific than "slug." |
Where was I? Oh, right,
the English physicist, James Prescott Joule
(1818-1889), established the mechanical
theory of heat and discovered the First Law
of Thermodynamics, which assures that energy
cannot be created or destroyed, only
converted from one form to another.
The joule is named in his
honor. Earlier...
...a French mathematician and
engineer, Nicolas Leonard Sadi Carnot
(1796-1832), produced the first account of
efficiency in heat engines, the Carnot
cycle, leading to the Second Law of
Thermodynamics, which forbids the complete
conversion to mechanical work of any other
form of energy. There will always be
some left-over energy given off as heat, the
lowest
form of energy. Even earlier...
...a Scottish inventor and
engineer, James Watt (1736-1819), made
improvements to the steam engine, which
played a prominent role in the Industrial
Revolution. The watt is named
in his honor, but watt is a
unit-of-measure for power not for
work or any other form of energy.
Power denotes the rate of energy
production or usage. For electrical
energy, there is the watt-hour or kilowatt-hour,
on which electric utilities base their
bills. That's about as close as most
Americans ever get to the metric
system. Accordingly, we see that...
...the joule
originated as a unit-of-measure for
electrical energy and is equal to the work
done when an electrical potential of one volt
produces a current of one ampere
passing through a resistance of one ohm
for one second, which amounts to
one watt-second or one newton-meter
-- the latter, only if 100% of that
electrical energy could be converted to
work, which is not possible.
|
 t the time of
that freshman prank in 1951, you could get your
gas-tank filled with "ethyl" (fuel tinctured with
'tetraethyl lead') and have your windshield cleaned
for three bucks. It is fair to say that the
subjects of energy and work are no longer confined to
the physics classroom.
Energy is an issue -- often a crisis --
that has captured the awareness of the public-at-large
over the decades since then. Today, though,
people think of energy as being measured exclusively
in gallons not ergs. But wait,
let's remember that...
- erg (n.) was coined in 1873
by the British Association for the Advancement of
Science from the Greek ergon "work."
- urge (v.) 1560 is from
Latin urgere "to press hard, push, drive,
compel," Greek ergon "work," orgia
"religious performances," organon "tool;"
Armenian gorc "work;" Lithuanian verziu
"tie, fasten, squeeze," vargas "need,
distress;" Old Church Slavonic vragu
"enemy;" Gothic waurkjan, Old English wyrcan
"work;" Gothic wrikan "persecute," Old
English wrecan "drive, hunt, pursue;" Old
Norseyrka "work, take effect."
 hile the world
approaches the end of the Petroleum Age, most people and
many policy makers are fervently wishing for alternatives.
Wishing
won't work (ugh). As you see above, the
words "erg" and "urge" share a common etymology.
At this point, I am again
tempted beyond my powers to resist and offer the
following coinage: the word "urge" as a companion for
"ugh," to serve as the unit-of-measure for political
work.
Meanwhile, here are a
few groaners based on
units-of-measure received from correspondents during the
late 20th and early 21st century.
> Ratio of an igloo's circumference to its
diameter: Eskimo Pi
> 2000 pounds of Chinese soup: Won ton
> One millionth of a mouthwash: One
microscope
> Time between slipping on a peel and
smacking the pavement: One
bananosecond
> Time it takes to sail 220 yards at one
nautical mile per hour: Knot-furlong
> 365.25 days of drinking low-calorie beer
because it's less filling: One lite
year
> 16.5 feet in the Twilight Zone: One Rod
Serling
> Half of a large intestine: One
semicolon
> 1000 aches: One kilohurtz
> Basic unit of laryngitis: One
hoarsepower
> Shortest distance between two jokes: A
straight line
> 453.6 graham crackers: One pound
cake
> One million microphones: One megaphone
> One million bicycles: Two
megacycles
> 2000 mockingbirds: Two kilomockingbirds
> 10 cards: One decacards
> One kilogram of falling figs: One Fig
Newton
> 1000 cubic centimeters of wet socks: One
literhosen
> One millionth of a fish: One microfiche
> One millionth of a phone: One microphone
> One million phones: One megaphone
> 10 rations: One decoration
> 100 rations: One C-ration
> Two monograms: One diagram
> Eight nickels: Two paradigms
> Three statute miles of intravenous tubing
at Yale University Hospital: One I.V. League
> One word: One millipicture |
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