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wrote:

I am 240 pounds 'mass' on earth. That's a fact.

I am 240 pounds 'mass' on moon. That's a weird assertion!

You've got me totally buffaloed now. I can't imagine what your
problem is.

Sure, mass is an ambiguous word, with several different meanings. But
there is only one of its meanings that is normally used with numbers
to express a measurement of its magnitude.

If that assertion is true, who changed the density of the moon??

What in the world would the density of the moon have to do with your
mass?

It would be more understandable if you were having a hard time
understanding the normal definitions for this particular context of
the ambiguous word 'weight,' as it is quite properly and legitimately
used for body weight of humans in medicine (including space medicine
by NASA astronauts and doctors), and in sports, the normal reasons we
weigh ourselves, and in the science of anthropology as well. Or as
the word 'weight' is also used in zoology and veterinary medicine and
paleontology for the weight of other animals as well as humans. Now
certainly, in any of these contexts, this quantity will sometimes be
referred to as 'mass' as well; that is also quite proper and
legitimate.

My 'weight' is 230 pounds on earth. That's a fact.

My 'weight' would be 230 pounds on the earth's moon. That's also a
fact.

Let's review what I've already posted in other messages in this
thread, from ASTM

. . . thus, when one speaks of a person's weight,
the quantity referred to is mass. . . .

and from NIST

Thus the SI unit of the quantity weight used in this
sense is the kilogram (kg) and the verb "to weigh" means
"to determine the mass of" or "to have a mass of".

Examples: the child's weight is 23 kg

You know damn well that those kilograms are used for body weight all
around the world, including most hospitals in the United States. They
are indeed the proper SI units for this weight (which, as I pointed
out above, is also sometimes called "mass" instead). Furthermore, as
you've already seen many times over in the past few days, pounds are
by definition exactly 0.45359237 kg.
http://www.ngs.noaa.gov/PUBS_LIB/Fed...doc59-5442.pdf

THE REAL WORLD, AND THE REAL MOON

Now let's look at something different, not dealing with imaginary
transportations of you or me to the moon, but with the real world, and
the real moon.

What do you suppose it means when NASA tells us that the weight of the
Apollo 11 Lunar Module was "10,776.6 lbs" at the time of liftoff?

What ...

Whoops, just about forgot where I was and got ahead of myself,
forgetting that I need to slowly spell out what might be obvious to
people in other newsgroups. The Lunar Module at liftoff, of course,
was in actual fact located right ON THE MOON.

Now, what do you suppose those pounds are? If you really have no idea
how big the Lunar Module is and what its weight might be on the moon,
here's a big hint. NASA also tells us that the same Lunar Module at
the time of docking had a weight of 5738.0 lb.
Selected Mission Weights
http://history.nasa.gov/SP-4029/Apol...on_Weights.htm

Where was this LM at the time of docking? That's when it caught up
with the command module, where Commander Collins was at that time
"weightless" in an entirely different definition of the word weight,
in free-fall orbit around the moon. But not only was he not
weightless in the definition being used by NASA for this LM weight,
though he also was far from weightless in the definition of "weight"
as a force as used by Sears and Zemansky, from whom you claim to have
learned your physics. Much less in terms of force units than he would
have been on Earth (about a tenth as much, only an order of magnitude
guess), of course, but far from zero, in the Sears and Zemansky
definition of weight.

[Sears and Zemansky, 1970 page 61]
5.5 MASS AND WEIGHT
The weight of a body can now be defined more generally than
in the preceding chapters as the resultant gravitational force
exerted on the body by all other bodies in the universe. . . .

There is no general agreement among physicists as to the
precise definition of "weight." Some prefer to use this term
for a quantity we shall define later and call the "apparent
weight" or "relative weight." In the absence of a generally
accepted definition we shall continue to use the term as
defined above.

The NASA site discussed above, of course, is not some aberrant web
page. Nor is it some alteration of the units by the NASA public
affairs office--this is straight from the scientists and engineers.
This is indeed normal NASA usage, to call this "weight." It is also
normal NASA usage of the units "pounds." We even know that this is
exactly the term under which it was programmed into their onboard
computers, and the units used there as well, because we have dialogs
between Ground Control and the astronauts in which they are reading
out these figures for something called "weight" on both ends of the
conversation, and those weights are in pounds mass. You also
routinely see the same usage of the word weight when NASA talks about
the weight of the space shuttles or the weight of components of the
Space Station, or the weight of the spinning satellite some
spacewalkers wrestled into submission a few years ago..

As an aside, what do you think: Will NASA ever learn the lesson of
the Mars Climate Orbiter, and quite using pounds?

--
Gene Nygaard
At the present time, however, the metrical system
is the only system known that has the ghost of a
chance of being adopted universally by the world.
-- Alexander Graham Bell,1906