We often hear how the humanities don’t offer much practical benefit, so here is a STEM application that I taught to some university physics students last week.
It’s about misconceptions. We all have them, I believe, and by their very nature, we usually don’t know it. I discovered only a few months ago that I hadn’t properly understood Brewster’s Law, in spite of having previously specialized in experimental optics, using apparatus that made use of Brewster’s Law to produce polarized light beams.
I carried that misconception around for fifteen years, not knowing that it was wrong. It was well integrated into how I lived my life, and didn’t draw attention to itself by causing problems. Not even when I was doing research in the lab.
Not causing problems is how misconceptions so easily survive. Actually, they can cause problems but, as long as you don’t suffer enough to notice, you won’t mind. Think of all those people who leave fans on to cool the room when they’re not there. The fans actually elevate the temperature, but not enough for normal people to notice, and certainly not enough to overcome the evaporative losses from your skin and clothes when you return.
This misconception isn’t quite harmless, though: it wastes energy, and increases the demand on energy supplies, hence increasing the pollution produced by power stations and the consumption of natural resources.
Plus, those of us who know what fans do are driven mad by this action. It turned out that there was quite a group of us who all felt exactly the same way. But people who leave fans on in their absence just dismiss our torment as trivial eccentricism.
Another misconception that causes no pressing problems is that the seasons are caused by our varying distance from the sun. We’re closer in summer, so it’s hotter. Never mind that the southern hemisphere has it opposite.
Though that can be accommodated by another misconception: that the earth’s tilt puts one hemisphere closer to the sun than the other, and the two swap over for the other end of the year. The harm caused by this is perhaps best measured not in terms of gross domestic product, but in how much hair astronomers pull from their own heads on hearing what people really think.
There was a time, though, when cosmological order did have serious consequences. You can read about the Galileo story in many places, and often it’s told with all manner of misconceptions such as Galileo being right — which is fine if your definition of science doesn’t require empirical evidence.
The fact is that Galileo had nothing to show that his newfangled preference was any better than the status quo, and he was asking the whole world to change regardless. To his credit, he did propose a way to tell whether the earth moved: he explains how close observations of the stars would reveal subtle motions best explained by the earth orbiting the sun. Actually making those observations is another matter. They’re so subtle that they had to wait for suitable telescope technology, and weren’t seen for another two hundred years.
From lessons like this, we can extract a simplified model that’s useful in the classroom, at least for smaller misconceptions.
The first thing to notice is paradigm shift. The big misconceptions involve changing how we perceive and conceptualize. It’s more complicated and deep-seated than just erasing one idea and replacing it with a correction. We’re aiming for conceptual change.
The second thing is conscious choice between alternative possibilities. We need to be aware of the difficulty: that we’re pulled in two different directions by an essential tension that leaves us unsettled and motivated to choose. I achieved that in the physics class by getting the students to articulate their reasoning in detail, until eventually they realized that they had no consensus, and argued over what to do. With no evidence, though, there was no way to definitively resolve their uncertainty.
How can we make the right choice? We need something to tilt the balance decisively in favor of one option, leaving the other in the dust. Something like a crucial experiment whose results can be readily explained by one option but not the other. So I told the students to go to the lab some time, and try setting up a test of their ideas. Maybe I could have just told them the answer, but science ought not depend on the blatant assertions of some historian, and besides, there’s more fun in going to the lab.
These concepts are simple enough, at least at the level needed for developing STEM lesson plans. But there’s no need to stop here: Thomas Kuhn’s the source on paradigm shift (The structure of scientific revolutions and The essential tension), and Francis Bacon and Isaac Newton on crucial experiments. You can find a pdf copy Newton’s paper about his ‘New theory about light and colors’ on-line at the Royal Society. That paper, incidentally, also contains the answer to another misconception about what happens when sunlight passes through two prisms.
The experiment is a little harder to replicate than it might seem, but it’s not impossible. I recommend it.
