How to Make Introductory Physics Exciting (When You're Bored Out of Your Mind)

Posted by Mason on 4/16/18 6:06 PM


Why do many students find physics so boring? 

College-level introductory physics courses on Newtonian mechanics can feel quite...mechanical and dry for most students. On the other hand, cutting edge physics research asks and addresses amazingly deep questions like “what is all the stuff in the Universe fundamentally made of?” and “where did all this stuff come from anyway?”. 

The partial answers to these questions provided by contemporary physics are so baffling that most of the lay public has probably heard a popular science account of quantum jumps and black holes. And in my own personal experience, almost everyone that has heard of such strange phenomena is fascinated by them. This includes students of college-level introductory physics. 

However, there is a huge educational barrier between black holes and the billiard balls studied in a freshman mechanics class. Many years of training in advanced mathematics and physics, usually all the way up to the graduate level, are required before one can get to the fun stuff and start answering questions like “what’s going on inside a black hole?” and “what does it mean for a particle to be in two places at once?” using formal mathematical reasoning.

Due to this formidable barrier, combined with systemic pedagogical traditions in the assignment of mundane exercises, students taking introductory physics courses are often bored with the material. On top of this, most students come into the classroom without planning on pursuing a graduate degree in physics. A result is that these students will likely become discouraged because they won’t be sticking around long enough to study the physics behind the mind-bending stories they’ve seen on Nova specials.

As a physics teacher and a researcher, seeing this boredom and discouragement in the classroom breaks my heart. So, I’ve spent some time thinking about how to make basic physics concepts more exciting and would like to share an example of a strategy I’ve used both in the classroom and as a private tutor that seems to have been effective in piquing student interest.

Bridging the gap between cosmic truths and textbook exercises

To illustrate a strategy that I have employed to attempt alleviating physics students’ boredom via two examples, I need to briefly introduce some physics bear with me (no equations, I promise!). 

Newton's Law

It is part of the standard curriculum in a freshman level college course on Newtonian mechanics to discuss Newton’s universal law of gravitation. This is the theory that Newton developed, legend has it, after experiencing a flash of insight upon being struck on the head by an apple falling from a tree1.

The law tells you the strength of the gravitational attraction force between any two massive objects (such as the apple and the Earth) given their respective masses and the separation distance between them.

Associated with the gravitational attraction force between two massive objects is an energy called the gravitational potential energy. As two such objects (stars, planets, black holes, etc.) accelerate towards one other under the gravitational attraction, this potential energy is released and converted into the kinetic energy of motion

Conventional textbook exercises give students the locations of two massive objects and ask the student to calculate the magnitudes of the gravitational force and potential energy. And that’s it. Once these numbers are calculated, the story is over. Time to move on to the next topic. In my view, this is a tragedy. It is tragic precisely because of one very important detail.

Newton's Constant

Contained in Newton’s formula for the gravitational attraction force is an incredibly tiny number, called Newton’s constant. The smallness of this number explains why the gravitational force only becomes noticeable when the masses of the two bodies attracting each other are incredibly large, as is the case with stars and planets, and is of negligible strength when the bodies involved are human-scale in their size. 

The ancients referred to the stars and planets as the “heavenly bodies” and their appearance in the night sky has inspired philosophers, poets, theologians and scientists since the dawn of civilization. Learning a fundamental law of motion that governs these heavenly bodies should be accompanied with a heavenly, or cosmic, perspective.

In order to lead my students toward such a cosmic experience, I ask them the following question:

How much energy does it take to assemble a star from cosmic dust?

That is, if I bring in cosmic dust particles, speck by speck, from distant reaches of the Universe, and grow a spherical star of a given size, what is the energy difference between the initial state of the Universe filled with diffuse cosmic dust and the final state containing the star we assembled?

It turns out that the energy difference is negative! This means that assembling the cosmic dust into a planet is a more stable configuration than having that dust dispersed throughout vast stretches of spacetime. That is, given a universe filled with cosmic dust and the fact that the gravitational force is attractive, stars will spontaneously start forming in such a universe (spoiler alert: this is what actually happened in our Universe). The attractive nature of the gravitational force is encoded by a negative sign in the mathematical expression discovered by Newton. The fact that the night sky is filled with a bunch of twinkling lights is directly traceable to this negative sign.

In addition to carrying out a standard computation of gravitational potential energy using a combination of physics intuition and integral calculus, the student, hopefully, leaves this exercise learning how their hard work invested in performing this computation is directly connected to cosmic phenomena and a deeper understanding of how the Universe works.

It is my firm belief that physics educators are tasked with the responsibility of providing students from all backgrounds with the type cosmic perspective that I have attempted to illustrate above; that communion with Nature through mathematical reasoning is possible to achieve even at the level of introductory coursework.

1For historical accounts of this embellished legend see:

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Craving more on the subject?  Check out some additional blog posts below:

Introduction to Physics: The Language of the Universe

How to Solve Kinematics Problems: Using Vectors

Physics Tutor: What is Moment and How do you Calculate it?