The Platinum Plover Egg

By Phil Pennington

Have you ever pointed out something that seems obvious and realized that others just didn't “see” it?

As a physics professor, I demonstrated Newton's laws of motion to hundreds of students. On my exam I presented them with the "bouncing ball problem": What is the direction of the acceleration of a bouncing ball as its velocity changes from down to up? I expected most students would see the answer as very obvious. My best classes got about 5% correct; other classes got about 50% correct—that expected by pure guessing. Apparently my students had not discovered... something!

A growing number of physics teachers are coming to realize that a majority of their students didn't see the “simple but subtle” principles that teachers have been pointing to for years. Many of these physics teachers are turning their attention to the problem of “not seeing,” and some very promising insights have come out of their research. From the learner's viewpoint, these results might be synopsized as:

Ask not to be taught
Learn—discover—how to learn.
And then, to understand,
Learn through discovery.

Unfortunately, this is not the view of most teachers, who see teaching as an expert (themselves) standing in front of novices and demonstrating the behaviors students should learn to emulate. Teaching, however, seldom leads to “seeing” or to the depth of understanding students achieve through discovery.

The profound, qualitative difference between science and pseudoscience is, like the principles of physics, “obvious” to those who see it. It may be thought of as a subset of the problems of the physics teacher. Movie goers, TV viewers, even “readers of serious literature are given the tacit message that the line between the natural and supernatural is blurry, and perhaps even nonexistent,” wrote Douglas Hofstadter in a recent Science essay, “Popular Culture and the Threat to Rational Inquiry” (July 24, 1998). To those who see the line, it looks pretty sharp; very few beliefs are hard to classify as either science or pseudoscience. But if movies, TV, and serious authors can present scenarios that suggest substance in the pseudo, then that line must be going widely unseen.

Skepticism is seeing that line. It's seeing simple but subtle principles in obvious, yet widely unobserved, phenomena. Hofstadter regrets that our culture gets “misled into accepting the implicit message that science is boring, conservative, closed-minded, devoid of mystery, and a negative force in society.”

Skepticism is not closed-mindedness; it is thinking that sees those simple principles of science. One good goal of skeptics is to find ways to help others see that line. Let's turn away from teaching and towards exploring mysteries—to discovery.

Discovery statements
Here is a discovery tool I have used. Often we see or hear a statement which gives us clues that something wasn't quite understood. For example, can you spot the misunderstandings that are suggested by the following statements?

  • Windows 95 made a quantum jump (a leap!) into the future of operating systems.
  • The earthquake's epicenter was two kilometers below Northridge, California.
  • Congress set the parameters for the budget, and then special interests tried to exceed them.
  • Earth rise on the moon. (A caption for a photo of Earth from the moon.)
  • An effective Private Investigator must use his fists, just like in the movies.
  • It will take light-years to solve the problem of eliminating war among mankind.

    I often hear statements such as these. Most people, if they “see” the errors, are likely ignore them because they usually seem trivial and inconsequential. Most are points that a majority of people consider to be established fact simply by usage; language is, after all, usage-defined. But if you scrutinize the statements a little more closely it becomes obvious they are really points of missed logic. They are simple but subtle points that lie at the edges of (easy) human comprehension, points that sometimes underlie pseudoscience.

    Perhaps our “seeing” these misunderstood statements will offer us a starting point for helping at least some people see into the abstract territory of physics and to that place where the line between science and pseudoscience is obvious. Let's, as skeptics, collect such starting points, these misunderstood concepts, and explore their use. Once in hand, we use them as discovery paths to widely missed points. For each such statement we should identify the missed point, a clue, and perhaps some societal consequences of that missed point.

    I have put a few dozen of these into an experimental web site where they are part of a puzzle-solving game. The game is a demonstration, an experiment with using this approach to reveal the simple but subtle concepts of physics. It's an “Adventure Cave” game like that of the ancient days of CP/M computers. You start in a gully next to a small building near some woods; you type in the direction you would like to go and the actions you would like to take. Soon you are in a huge cave full of secrets and secret passages, magic and mysterious forces, trolls and wizards ready to help or hinder. And somewhere there is a golden plover egg to find.

    My web site has a platinum plover egg. It's well hidden, but the clues necessary to find it are there. And along the way there are many clues to help find the obvious yet unobserved line separating science from pseudoscience.

    Let's develop this technique to reveal the true mysteriousness of science which today's open mindedness has let leak out of New Age minds. This could be the beginning of a long journey of true discovery. I would like to hear about some of the examples you encounter. What are the clues, what was missed, and what might be some consequences? And how might we structure a presentation that could direct someone toward that “Eureka” insight?

    Statements that Give Clues

    Examine the statement: “An effective Private Investigator must use his fists, just like in the movies.”

    The clue: A movie critic once commented, “The loud cracking sound you hear when the movie hero punches the villain in the jaw is the sound of finger bones breaking. Jaw bones are stronger than finger bones.” A few years ago several professional basketball players demonstrated the critic's point by throwing a few angry punches. We heard of no broken jawbones, just a lot of broken fingers.

    Missed: Newton's law of action and reaction (third law of motion), which is the observation that forces are always interactions between two objects. The force on one object and the force on the other are equal in magnitude and opposite in direction. The two forces are inseverable parts of a whole, just like the two sides of a sheet of paper. This law is often mistakenly thought to be simply a statement that causes have effects, and effects have causes. But to Newton it was a previously unrecognized, profound insight into why the moon, planets and sun move the way they do.

    Another common mistake is believing that intent is important. The hero did the hitting, but the villain hit too—with his chin. Newton says, “The force on the chin equals the force on the fingers, but in the opposite direction; the fingers, being weaker, break.” Seeing intent, instead of the physics, as important to the outcome is an egocentrism, which, it seems, is difficult to overcome.

    Newton's third law also involves the relationship of mutual reciprocity: A is to B as B is to A. This is one element of symmetry, a set of abstract concepts prominent in modern physics. Carl Sandberg in the tall-tales chapter of The People, Yes tells of “skyscrapers so tall they have hinges on their tops to let the moon go by, and pancakes so thin they have only one side.” It is the symmetry of mutual reciprocity that underlies the humor of the pancakes. It's only a short step outward from comprehension of this easy concept to understanding mutual reciprocity in Newton's law of action and reaction—or even Einstein's energy-mass equivalence and Harvard sociologist Lawrence Kohlberg's social “implications of mutual reciprocity.”

    Our blurry vision of mutual reciprocity leads us to perceive but one side of the two inseverable parts of a whole. It deceives us into thinking that intent breaks the jaw; that mass and energy are distinct entities, and mass gets “converted” to energy; and that perpetual antagonism as portrayed in the movies, rather than cooperation, is the “real stuff” of life.

    About the author:
    Phil Pennington is a retired physicist who taught on the faculty at PSU and has a special interest in problems of education and the misunderstanding of physics. You can find part of his game on his personal web page, located at and you may obtain the entire game on floppy disk by contacting him by e-mail at:

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