I agree the phrase "energy is the ability to do work" is problematic.
However, I find it is quite common, and many students come to college
with this phrase as part of their world view. Therefore, rather than
ignore the phrase, I have to spend some time telling the students
what's wrong with it.
Unfortunately, the students (both the bright ones and the not so bright
ones) want to know what to put in its place. About the best I can do
is tell them that energy is a concept in physics that helps us
understand some aspects of nature, and using the energy concept
sometimes allows us to calculate something that otherwise might be very
difficult to calculate.
That type of explanation helps, but seems lacking, especially to the
less-bright students who often need a more concrete definition or
analogy to help them grasp things.
I am curious if any of you have developed statements about energy that
are less wrong than "ability to do work" but more tangible than "a
useful concept."
Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817