In March 2012, Fernand Brunschwig, Chair, STEMteachersNYC and editor of Robert KarplusÕ textbook for non-science college students, Introductory Physics: A Model Approach, posted the  note below to the physics modeling listserv. In October 2014, he gave me updated URLs, which are here, in place of the outdated ones.  – Jane Jackson


I quote Fernand Brunschwig in March 2012.


Energy as the ability to do work is a definition that is suited for the traditional approach that makes mechanics the foundation for all of physics, which is what most or all physics courses do.


At least for a "liberal arts physics" or a "physics for the general public," and probably also for a "physics for scientists and engineers" course, I think, with Richard Muller, that it is better to start with a more general definition that can more easily be seen to include thermal phenomena.


In Introductory Physics: A Model Approach, Ch. 4 ("Matter and Energy"), Robert Karplus begins with "the inherent power of a material system, such as a person, a flashlight battery, or rocket fuel, to bring about changes in the state of its surroundings or in itself." [You can freely read the chapter at Log in as <guest> and use the password <guest>. JJ]


I also recently organized and conducted a workshop on teaching energy for PhysicsTeachersNYC [later called STEMteachersNYC – JJ], for which I developed a series of energy diagrams that, I believe, would be useful in teaching energy using Karplus' approach. My idea is that students could be shown one or two of the simpler diagrams so that they would understand the meaning of the flow arrows and the way that the before/after bar charts must reflect conservation of energy, and they could then be asked to complete some of the diagrams with the energy flow arrows and the levels on the energy bar charts omitted.


Here's the URL where I've published 4 of the energy diagrams [by 2014, many others too – JJ]:

1. Ball thrown vertically:
2. Carry backpack up hill:

3. Person pushing crate across floor:

4. Car braking

I've created other diagrams, with and without the arrows and values on the bar charts, which I could publish if others are interested.