Re: weight vs. mass (was: Units and Conversions)

["John S. Denker" <jsd@MONMOUTH.COM>]

Tina Fanetti wrote:
> Okay this is slightly off topic but not much.

It seems well within the phys-l charter.  If you don't like
the Subject: line, change it.

According to standard netiquette
  http://www.faqs.org/rfcs/rfc1855.html
    "Mail should have a subject heading which reflects
    the content of the message."

[regarding weight versus mass] ...
> Should I just go along or teach them properly?  My inclining
> as a physicist is to teach them correctly but realistically

Seems like an easy choice.  There are advantages to the
correct approach, and no disadvantages AFAICT.

> I don't think they are going to get it.

What makes you think that?
What's not to get?

Suppose astronaut A tosses a banana to astronaut B
  http://www.christiananswers.net/kids/banana.avi
Is the banana weightless? T/F
Is the banana massless?   T/F
Does Newton's second law apply to the banana? T/F

See also:
  http://www.monmouth.com/~jsd/physics/weight.htm

===================================

>  the math book uses weight and mass nearly interchangeably.

For a math book, that's not the least bit unusual.
There are lots of real-world situations where, depending on
context, it may or may not be appropriate to
 -- distinguish between cows and steers
 -- distinguish between blue and cyan
 -- distinguish between lawyer and attorney
 -- distinguish between weight and mass
 -- et cetera.

Sometimes it matters, sometimes it doesn't.  Even if _you_
are super-precise all the time, you can't expect everybody
else to make the distinctions when they don't matter.  But
you _can_ insist that people in your class learn to recognize
when it does matter, and to do it right when it does matter.