Grasp of Concept: What are yours?

One thing I’m certain all physics teachers develop over time is new and varied ways of talking about physics concepts–especially ways that are more informal than textbook definitions. These informal ways are less focused on giving a precise definition and are more focused on trying to offering insight into a concept through metaphor, image, story that provide a grasp of concept.

Here is an example of an informal way of talking about net force

When multiple forces act on an object simultaneously, it’s useful to think of their combined efforts as being equivalent to a single hypothetical force–one with just the right direction and just the right magnitude to cause an identical acceleration. We call this Net Force.

Net force is NOT an additional force that acts on the object, but a measure of what a “team” of forces accomplishes together when acting on the object. Experiments suggest that when individual forces act together on a single object, the net force is equal to the vector sum of the individual forces.

This property of forces appears to be universally true, and scientists refer to this as the principle of superposition.

What are concepts for which you think you have developed powerful ways of talking about them? What are the concepts? What are they ways of talking about them?

Note: I am not under any illusion that me saying these things is of utter importance for learning, for I know it is students that must do this type of construction for themselves. That said, having such varied ways is critical to being able to help students do that construction.


2 thoughts on “Grasp of Concept: What are yours?

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  1. My never before shared electrostatics McSparkle; Pretty far out there and even less formal but I theatrically paraphrase Winnie the Pooh story when he gets stuck in rabbits hole (like proton is stuck in nucleus). Came to me in shower years ago. Pooh is + and starts w P. Bet you can guess how to weave Eeyore, this sad nomad, into the works!
    Got some props and made a 100 acre wood scene for fun.

  2. Nowdays, I try to use a lot of different resources to provide a grasp of the concept. One of them is to ask what questions would you formulate in order to know something about a physics idea, for example, about force. I ask my students to write and discuss those questions.
    One thing that I would like to do is ask the students to take some photos that they think represents the concept.

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