The direct result of that approach, i.e., that weight is gravitational pull, is that students will assume there is no gravity in space because astronauts are "weightless". In fact, one hears students saying that frequently. I hear it most from my meteorology students rather than my general physics students because that is what they took away from their high school physics course (weight is gravity).
Bob at PC
________________________________________
From: phys-l-bounces@carnot.physics.buffalo.edu [phys-l-bounces@carnot.physics.buffalo.edu] On Behalf Of William Robertson [wrobert9@ix.netcom.com]
Sent: Monday, November 08, 2010 11:00 PM
To: Forum for Physics Educators
Subject: Re: [Phys-l] definitions ... purely operational, or not
My specific take on it is that it works just fine. My particular
interest now is how teachers view the definition and how it affects
students. Like it or not, most elementary and middle school students
learn the difference between mass and weight as the fact that mass
does not change when we go to the moon, but weight does. That only
works if weight is defined as the force of gravity acting on an
object. If weight changes all the time depending on the viewer's frame
of reference, then all we have is confusion for the students. When we
say that objects "weigh less in water" or other conventions, then it's
confusing for students. Even young students can understand relatively
abstract ideas, but not if we all use different definitions.