Science Teachers: Teach the Truth
I was at an FBO (airport gas station—incidentally, this means very, very wealthy people are frequently around. I assure you, they do not inspire). Anyhow, I was there awaiting some maintenance on the helicopter for an afternoon the other day and I couldn’t help but notice that on the TV was a silly show where a “Science is fun!” guest teacher was visiting an inner city school to pep up the otherwise dry material.
It caught my attention, as you might expect, faithful reader, because the topic of my guided reading through the Great Books of the Western World is “Foundations of Math and Science”. So when I hear, “Newton”, “Force”, “Inertia”, and certain other keywords, I am always interested to take a closer look.
The particular concept the energetic guest was bringing to the kids was inertia. His whole game was to demonstrate inertia by yanking the tablecloth from under some dishes as they remain in place.
He says, “Inertia: the tendency of an object to stay at rest until a force acts upon it.”
The definition isn’t troubling. The troubling thing is…can you name it with me? On three. One, two, three: Everything in the universe is demonstrating it!
Whether this zany, cooler-than-your-teacher (and actually, kinda disrespectful) man shows up to a school and says the words “learn” “newton” “inertia”, or not, inertia is demonstrated by not only every object in a student’s immediate observation, the student’s body itself, but also by every object in the entirety of the universe!
But the man adds, “Isaac Newton would be so proud that you’re learning!!”
And there is the whopper. Isaac Newton would be proud if kids were learning (they’re not), but he would not be proud that a man claiming to be an expert is teaching kids that he is demonstrating inertia.
With me?
Inertia isn’t “demonstrated”. Inertia is.
“Pete, you’re being way too sensitive here.”
Am I?
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Why does learning have to be fun?
From what I have read, the math and science greats do not seem to have had much fun while attempting to communicate their ideas. Moreover, many of their lives were fairly difficult—as they were battling commonly held conceptions held by nearly each and every fellow man.
Instead of “fun”, I say let’s teach the truth to kids.
Straight from the man.
Definition III from Isaac Newton’s Mathematical Principle of Natural Philosophy.
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The vis insita, or innate force of matter, is a power of resisting, by which every body, as much as in it lies, continues in its present state, whether it be of rest, or of moving uniformly forwards in a right line.
This force is always proportional to the body whose force it is and differs nothing from the inactivity of the mass, but in our manner of conceiving it. A body, from the inert nature of matter, is not without difficulty put out of its state of rest or motion. Upon which account, this vis insita may, by a most significant name, be called inertia (vis inertio) or force of inactivity. But a body only exerts this force when another force, impressed upon it, endeavors to change its condition; and the exercise of this force may be considered as both resistance and impulse; it is resistance so far as the body, for maintaining its present state, opposes the force impressed; it is impulse so far as the body, by not easily giving way to the impressed force of another, endeavors to change the state of that other. Resistance is usually ascribed to bodies at rest, and impulse to those in motion; but motion and rest, as commonly conceived, are only relatively distinguished; nor are those bodies always truly at rest, which commonly are taken to be so.
(My underline.)
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If that doesn’t do it for ya, if you still don’t understand what Newton means by the word inertia, then the only sentiment I may offer as a last ditch effort is this.
Imagine a man moving while inside a moving vehicle. Got it? (It doesn’t have to be a car with a man reaching back to grab a snack from the back seat, or a pirate ship approaching a storm while the captain paces to and fro by the helm, or an airplane with a man squeezing down the aisle after a bathroom break. It can be any vehicle, any person, but the vehicle and the person inside must be moving.)
That is the Newtonian picture of the universe as described at the end of that definition. Because, Newton says, the vehicle we’re in (which you didn’t know we’re in—and he doesn’t mean merely planet Earth) is moving; there is no “rest” in the plain sense.
Inertia, then, is the conception (defensible by math and experimentation) that all bodies resist. It’s an action. Or a force. To resist, there must be something to resist. (Period.)
And I’m out.
One more clarification: the main evidence of inertia is all the different bodies (objects) do not float around, untethered-like. And keep in mind that inertia is just the name Newton suggested for the force he believes exists. He’s not claiming to have invented the force. So don’t get hung up on “but I thought inertia meant…” The skill here is understanding (and then teaching each other) what Isaac Newton meant.
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