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But how SHOULD we teach kids about 'electricity'?
1997 William Beaty

This is the one thing I lack, good replacements for the incorrect material in K-6 textbooks. I'm not a teacher, so I lack the experience in teaching children. I would need experience to create good curriculum material. In the following, keep in mind that I'm an EE (electronics designer) who complains about the accuracy of info in textbooks, but without having the benefit of actually being an educator USING any of these textbooks while teaching.

Note that the problem with electricity misconceptions is mostly in K-6 texts and children's books. In my experience it appears to be limited to highschool grades and earlier. For good and reliable information , textbooks at the undergraduate college level are almost uniformly accurate. Unfortunately they all base their explanations on mathematics, and would require 'translation' before children or the public could understand their material. (And that's what my electricity website provides: translating college-level physics textbooks into everyday language/pictures/concepts which anyone can understand.)

I've only found one popular Electricity book which lacks nearly all the "infectious" misconceptions. Unfortunately it's out of print. "Basic Electricity JE-101" by Gene McWhorter It seems to be aimed at the middle high school level. It even has quizzes at the end of chapters. Unfortunately Radio Shack replaced it with "Basic Electronics", which lacks all the wonderful visual representations of beginning electrical science found in the eariler book.

For a K-12 classroom textbook which is far above average, try Prentice Hall's "Science Explorer" series, the volume on Electricity and Magnetism by Dr. C. Wainwright of the excellent CASTLE project. This one dates from 2007, and lacks the misconceptions I discuss on this site. I don't know if other Prentice Hall editions lack the errors, since Wainwright isn't the author, and few authors are aware of the textbook misconceptions problem (or aware of their own.)

For high school level, an excellent commercial curriculum package is the CASTLE material. It takes a conceptual approach to electricity education, and is widely used in high school physics classes. It concentrates on charge flow and energy transfer concepts, and doesn't contain all the misleading "electricity" contradictions. Here's an online copy of the student manual. The required kit of parts is sold by Pasco.

For K-6 grades there's also the old ESS " BATTERIES AND BULBS"[pdf] lesson plan from ESS and Delta Education, ISBN 0-87504-011-X. It's been around since about 1986 and is excellent.

My own attempt at some visual/conceptual introductory material is here: Explaining "electricity" with red/green plastic sheets.

If I were teaching, I'd concentrate on initially having the kids play with all sorts of real electrical devices. Batteries and bulbs, tiny motors, loudspeakers, maybe solar cells and LEDs (easily found at Radio Shack.) A secret: buy lots of "clip leads", wires with little alligator clips on each end. This lets you connect various devices together, even if the devices lack proper connecting terminals.

One particularly wonderful device is the "Genecon" hand-cranked generator, available by mail order from Arbor Scientific among others. (www.arborsci.com) It puts out about 8 volts DC max, and the polarity will reverse depending on direction of cranking. Unfortunately it costs over $50 each or so. Maybe too expensive to have 30 of them for the entire class! Look around and you can find other types for less than half the price.

At the very least, consider buying a single generator to play with.

Here's an electronics education secret: sometimes you can find digital voltmeters for well under $10 (even under $5 if on sale,) check out the multimeters at Harbor Freight Tools. Our city has a couple of those stores, so maybe yours does too (avoid mail-order shipping.)

Once the kids have had fun and maybe are starting to get excited about the mysteries in the wires, only then start on the more standard curriculum material.

For explaining how charge-flow and electrical energy works, my favorite simple demo is two clothesline pulleys and a loop of rope (with rope ends butted together and duct-taped.) This "rope-ic circuit" shows how the electric charges in a metal can be forced to flow in a circle. Drive one pully into motion with your hand, and that pulley becomes a generator. The other pulley is driven by the flowing rope, and it behaves as a motor. To demonstrate an open circuit, have one person turn a pulley, and have another person grab the the rope at some point in the loop and hold it still. To illustrate an electric heater or electric light bulb, let the moving rope rub against your thumb so your thumb gets hot. Or, to illustrate Alternating Current, turn one wheel rapidly back and forth to demonstrate how AC circuits contain charges which sit in one place and wiggle back and forth, while energy is still communicated to all parts of the loop.

If you can afford to buy a bunch of $4.00 clothesline pulleys, perhaps you can even have the kids expand it into a vast network of wheels connected by a single loop of string, all of which will turn when a single wheel is turned, and all of which will stop when the "circuit is opened"; when the string is grabbed in one place. (I haven't tried this myself. Don't know how easy it is.) The cellulose molecules in the rope can represent the electrons in a wire. Flow of the rope represents charge flow in wires. The push/pull tensions in the loop of rope represent electric voltage. The slow speed of the rope matches the slow speed of charge flow. The rapid transmission of "horsepower" from pulley to pully represents the electric energy which moves at nearly the speed of light in circuits. To show that electrons aren't so invisible, replace the loop of string with a loop of fishline. When you turn the pulleys, the fishline appears not to move (since it's very smooth.) Similary in wires, the charges are visible as a silvery metallic color (all metals have this), but when the charges all begin to flow along, we cannot see the silvery stuff start moving (since it is far too smooth, it has no marks which might show that it's flowing!)

Another similar "visible electricity" demo would be a circle of railroad track and a bunch of freight cars as the "electrons" (With no engine of course). Include enough freight cars so that you cover the entire circle of track. Then push one freight car along, and you transmit kinetic energy almost instantly to all the cars in the loop. The cars represent the copper's electrons which flow within a wire. Or, put a row of marbles in a circle on top of a large steel coffee can. If you can get hold of a bag of old golf balls, maybe you can fill a circle of model railroad track with large rolling "electrons" (N-gauge track might be needed, I don't know if golf balls will hit bottom on the standard HO-gauge track). Fill the entire track with balls, so when you push one ball, all balls must roll at the same time like a big flywheel.

Other stuff:

My usual suggestion is to abandon the terms "electricity," "current," and "power," and instead start out with as much correct terminology as you think is appropriate for that age level.

- We do not study "electricity", we study "electrical science."

- Generators don't produce "electricity", they produce "electrical energy" which is made of invisible fields resembling radio waves that whiz along outside of the wires. Generators are charge pumps. They force the charges found inside the wires to flow along.

- "Electricity" doesn't flow inside metal wires, charges do.

- Batteries don't supply "electricity", the wires do. A battery is a chemically-fueled charge pump. Like any other pump, a battery takes charges in through one connection and spits them out through the other. A battery is not a source of the "stuff" being pumped. When a battery runs down, it's because its chemical fuel is exhausted, not because any charges have been lost. (Remember that a battery is just a Fuel Cell, but it keeps its chemical fuel on board.) When you "recharge" a battery, you are pumping charges through it backwards, which reverses the chemical reactions and converts the waste products back again into chemical fuel.

- Light bulbs don't consume "electricity." Instead, the charges of the thin filament are forced to flow along much faster than they would in thicker wires, and this heats the filament because of a sort of "electrical friction". Charges are flowing into the bulb through one terminal, but then they flow back out again through the other terminal. The quantity of charges inside the filament doesn't change, and none are used up.

- As Michael Faraday discovered in 1939, there are no different "kinds" of electricity. Faraday states that only one kind exists, and the various supposed "electricities" are just situations where magnitudes of net-charge and charge-flow take on various values. There aren't many electricities, instead the topic of Electrical Science is divided into many subtopics such as "Electrostatics," "Electrochemistry," "charges," "current," "imbalanced charge," "sparks," even "voltage". See what Faraday says about this. Also see the electricity map for the fuzzy boundary between so-called "static" and "current."

- Avoid saying "static electricity" and "current electricity". Instead call them "charge imbalance" and "charge flow", or possibly "voltage" and "current". (A little known fact: static electricity involves high voltage. Also, even the flowing charges during electrical currents will always display the familiar "static electricity" effects whenever the voltage is high.)

- Even avoid saying "Current" entirely. After all, current doesn't flow in wires; charges do. Since the term Electric Current means the same thing as charge-flow, just simplify the lesson by talking exclusively in terms of charge-flow. (Analogy: when explaining water, we talk about water, rather than saying "current" this and "current" that.)

I've learned an important lesson from the "new math" debacle in the late 1960's. I don't want to become one of those experts who causes similar problems. As an educator, I have too much theory in my head and not enough teaching experience. If I were to write a K-6 science book, that book might appeal more to academics and engineers than to children and educators. Curriculum material should be created by teachers, not by content experts having only months of classroom experience.

If anyone should figure out more good techniques, lesson plans, activities, etc., then by all means get them onto the WWW so other educators can benefit. We can point our "Electricity" websites at each other.


 





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