Concepts is another word for idea. And in physics the word concept is applied to ideas as simple as speed to those which are grand schemes of thought like the General Theory of Relativity. But at all levels people will frequently experience difficulty as they try to understand physical concepts. And so what is the source of these difficulties?

One of the first sources of difficulty is the language we use. Names which we use for physical concepts such as energy, momentum, force, … are used routinely in our everyday lives. Yet the term in physics is a carefully constructed, sharply limited, definition. But because of the vague similarity between the precise physical concept and the word as we use it in out everyday lives, people often carry over their expectations of the word to physics. And so when they read in physics texts that by carrying a book in a horizontal direction at a constant velocity then they would do no work. This seems to make no sense because they would soon grow tired. This is of course an obvious disjoint but there are many other more subtle conflicts. Be aware of this problem.

A second major difficulty is that we have all developed expectations of physical phenomena based on our everyday experiences. And these sometimes are based on inaccurate or careless observations. Or physics may define a set of conditions seemingly the same, but very different, from our everyday experiences. And so when we read that objects in motion tend to stay in motion … this is not what we ’know’. And though we are trying to learn that objects fall at a constant velocity, we still expect Roadrunner to make it by running straight across the ravine while Wiley Coyote will not. Again I am using obvious conflicts which most people would pick up right away. But there are many, more subtle, pitfalls.

A third major difficulty is that many of the concepts we use in physics are inventions – ideas which we have developed simply because they make things easier for us to understand, to talk about, to study. But we rarely allow students the opportunity to explore how and why these concepts developed. And so instead of being able to plant these ideas on a firm foundation, students are often left to juggle new ideas while we ask them to build upon them a new body of knowledge, a new way of looking at things.

Most of the active learning strategies are designed to address these last 2 difficulties by asking students to engage in concrete activities which address misconceptions and allow students to build the concepts themselves. Unfortunately, because of time constraints, only a few of the concepts in the introductory course can be explicitly treated in this way.

And finally many of the concepts developed by physicists are hard simply because they are challenging. Subtle, abstract, elegant, powerful … these ideas will take a lot of thinking about and a lot of head scratching in order to make sense.

Regardless of the nature of difficulty we still hold students responsible for doing whatever is necessary to understand these ideas.

So do not think that because you are having troubles understanding the ideas that you are alone. Everyone has difficulty.

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