A Child’s Electricity
Field, Spark and Flow
It may seem odd to discuss electricity in the context of primary education. Indeed, when the first Casa dei Bambini was established there was no wide spread urban electrification. Italy was as dark at night then as North Korea is now. Electricity was not a factor in daily life.
Today, the child is surrounded by electricity: cell phones and other devices, outlets and batteries, a physical distribution grid much of which is in plain sight along side every street and road. We have become comfortable with the awareness that our own bodies are neural-electrical networks. We have even achieved direct neural connection with prosthetic devices such as pacemakers, cochlear implants and electromehanical limbs.
Electricity pervades the child’s human made experience. It also occurs and can be recognized and named in the child’s spontaneous, natural experience. There is the crackle of a sweater being pulled over one’s head on a cool dry day or the spark from a door knob after shuffling across a carpet. There is the drama of lightning in an electrical storm and the delightful flash of a lightning bug on a summer evening.
In short, we have every reason and the means, scientifically, culturally and naturally, to address the existence of electricity through the prepared environment right from the beginning, in early childhood.
By early childhood I mean that primary or “pre” school period between ages 3 and six. These ideas and materials could be introduced in the six to nine year period as well, but then the child would have had to wait unnecessarily.
We make students wait to experience basic physical phenomena in any organized fashion because we think that the subjects should be held back until the student has the ability to approach the mathematics that describe them, by which time the sensitive periods for and the fascination with profoundly simple, concrete experiences have passed. Just as the interest and easy with which a native language is learned fades. See also, Begin at the Beginning.
Fascination with physical events and energies begins before they are named, measured and conceptualized. Basic energies are simple and raw, like the sensation of holding opposed magnetic fields or being pinned to the hand bar of a fast spinning merry-go-round. The physical experience that is the foundation of an idea necessarily comes before the idea. Design of primary science equipment takes some thought, especially with regard to self-correcting independent use and manual dexterity. But building a primary physical science curriculum is easier and a good deal more interesting than you might think. The materials suggested here combine common objects and manufactured items readily available and reasonably priced.
The goal is to bring Electricity into the classroom as an easy going, everyday fact of nature, just as we present plants and animals, stones and bones. We need to present electricity’s basic physical reality, using the words needed to name it and the basic ideas needed to describe and discuss it.
THE BASICS
There are three manifestations of Electricity that can be presented on the child’s macro scale. They are Field, Spark and Flow.
- Electrostatic Fields, Action at a Distance
The fact that a static charge can be deliberately built up on the surface of an object is one of the first ideas. This is done with a piece of silk or wool and a length of PVC pipe. The wool should be knitted, as from a sweater, rather than woven as in a cloth. This is because courser wool will crackle as the charge passes from the wool to the plastic, smooth cloth not so much. That sound is a control of error. If you aren’t hearing it, its not happening. Likewise the electrical field around a charged surface, like a sheet of acrylic or a Styrofoam bowl can be felt with one’s hand sometimes as a “stickiness” and sometimes as an actual pressure on the skin and hair.
A charged static tube is a hand tool like a screwdriver. You can do interesting things with it. Unlike a screwdriver, the static field around the charged tube can be used to move objects without touching them. This is action at a distance and is vitally important as it demonstrates the existence of an invisible force field (a magnetic field being another) which lies beyond our senses but can be demonstrated causally. The reality of the extrasensory world in which we live is a an awareness which should be cultivated from early childhood.
Here are simple objects that can be moved with a static field.
- A Balance Bird. Made of plastic, bamboo or even just paper, a balance bird sits on it’s center of gravity minimizing friction and presenting a clear case of a force field moving an object. It is a stable, attractive piece of shelf work which challenges dexterity as well. Set the bird in its beak, charge the tube and spin the bird without touching it. Avoid balancing objects that are thick, hollow or balanced with weights as these will have too much mass and friction to react.
- A stream of water. A thin stream can easily be bent with a charged tube and is quite a pleasing demonstration for the young child. Basic demonstrations of energy flow and transformations should always include liquids and gases. Also the ease with which the charged object can be pushed into the water and accidentally discharged is a good control of error and an occasion to use the pertinent vocabulary, charge and discharge.
- An Aluminum Can. It is easy to push-roll a can across a table with a charged tube without touching the two together. Although, it is also possible to bring the two into direct contact and pull the can rolling along as it’s side slides against the rod.
- Importantly, two spheres or flat pieces of material hung side by side and simultaneously charged from a single source. These objects will repel each other. This reaction forms the basis of one of the first electrical measuring devices, the Electroscope.
Don’t forget clothing and hair. Kids move a lot. They tend to build up charge regularly, especially in winter. Tracing lines on, say, a sweater with an AC current tester will set the tester off as it discharges the material. A charged static tube can be used to move hair in one’s head and arms. This is a great example of what I call putting the child in the circuit, making their own physical bodies part of what is happening, in contrast to being outside of a work manipulating it or perhaps being reduced to just observing it.
2. Spark, Leyden Jars
It is literally possible to capture lightning in a bottle. A charge can be transferred from a static tube to a Leyden Jar, and just as when charging the tube, the transfer of charge can be heard as a crackling sound. This capture, store and release of electricity is the basis of of a fundamental electrical component, a capacitor. The importance at the primary level is the ability to manipulate electric charge and to do it at will.
3. Flow, Dynamic Electricity.
Sometimes a charge finds a conductive path or becomes strong enough to jump a gap. Lightning and sparks are gap jumpers. Sparks can be generated at will. The AC tester mentioned above will often generate visible sparks as it discharges a piece of clothing. Leyden Jars which can be charged with a tube and discharged with a spark to a wire or a finger. Sparks give us the definition of “ground”. Ground is where sparks go, literally, as will other movements of charge.
The limitation of sparks is that they are instantaneous and total. The third macro manifestation of electricity is a sustained flow of charge from one point to another. In the day to day world such flow is confined to conductors and so is invisible. However, a beautiful, easy classroom experience of interaction with moving tendrils of electricity can provided by a Plasma Ball; visible, sustained discharge in relatively slow motion that can be directed with a finger tip or the tip of your nose, if you like.
Numerous variations of guiding a tendril can be suggested, like counting, taking a tendril from one numbered dot to another, 1–2–3). The AC tester can be used to demonstrate the existence of the field outside of the ball. Just turn the tester on and move it toward and away from the ball causing the tester to react. Place yourself in the circuit. While holding the tester at arm’s length far enough away that it doesn’t react, place the other hand on the ball letting the field extend over your body lighting up the tester. Kids love this. It makes their hands the switch, literally.They can even form a line holding hands with the last child holding the tester and the first one touching the plasma ball.
Controlled Electricity.
Having presented electricity moving freely, we can present electricity being controlled. Grownups control electricity in amazingly complex ways. The primary level introduces two simple ones. Guiding with conductive materials and containment in batteries.
Batteries lend themselves to sort and order exercises. Batteries are instrumental to the ideas of polarity (+and -), direct current, measurement and importantly the difference between open and closed circuits.
Conductors, usually wires, but sometimes other shapes like rods or plates or our own bodies, keep the electricity inside where it cannot be seen, though occasionally it can be felt or heard. Conductors guide electricity to and through whatever devices or components we wish. Every circuit must be complete, leaving the battery and returning to it. If there is an opening, current cannot flow. Conducting materials shown in a primary setting include copper, aluminum, zinc, carbon, iron, steel and water. These, of course, are contrasted with nonconducting materials such as glass, plastic and wood inserted into an otherwise closed circuit.
Circuits should be built in two ways. One is with common objects, a basket of well chosen parts. The other is with a commercial circuit set. My preference is Snap Circuits by Elenco. It is important to show primary circuits in both formats. A proper kit presents consistent, formal components along with geometric layout on a board and count-ability (the connectors are also small numbered rods). A battery basket presents the idea that you can make these circuits with what you can find in many environments. A comparison of the connector types illustrates the point. Consider also the different dexterity required for a snap and an alligator clip.
Smart phones, incidentally, are a great tool in the presentation of circuits because you can build the circuit, photograph it and then present it as a diagram. Building a project from an image, which is reading a plan, is as basic a skill as reading text.
Energy Transformations
Electricity can be transformed into the other seven energies mentioned in, A Child’s Physics: magnetism, light, heat, sound, motion, chemical reaction, and consciousness, all using primary circuits. It takes a battery, a closed circuit, a switch, and the individual components: a conductive coil, a bulb or LED, a buzzer or speaker, a motor, a resistor and heat reactive film, conductive paddles or rods and a glass of water.
Energy transformations are reversible, requiring: a permanent magnet and a conducting coil, a solar cell, a microphone, a peltier device, a hand cranked generator, a fuel cell, a signaling device (sound and light being the two most common) and two logic circuits. The latter express consciousness by assigning meaning to changes in electricity.
Measurement.
Energy measurements expand the child’s sensory experience by indicating the presence of phenomena and associating numbers with differing amounts or strengths, thus quantifying. These are simple mechanical and digital devices that provide real information otherwise unavailable to the unaided senses. In this sense measurement precedes the formal definition of units. The child experiences the concrete changes in an energy, sees the indicated numbers, learns the appropriate terms to name the numbers. When possible use a an analogue dial as it takes advantage of the child’s sensitivity to moving parts. There are three primary sensors used with electricity.
- Battery checker. And a basket for spent batteries which includes one or two good batteries. This provides a “find the good ones” exercise which is very popular. It also gives us compare and order work.
- AC tester. The basic intended use of an alternating current tester is to prove the presence of alternating voltage at a wall outlet. We will not use it that way. An ac tester will react to any changing voltage. So it will indicate the presence of static charge moving to ground, like discharging a sweater. It will react to the field and tendrils of a plasma ball because these are constantly changing. Speed of flash and beep indicate strength of field. The tester can be combined with a digital tuner to locate specific notes.
- Volt/Amp meter. Snap Circuits includes a very simple meter. It is used to indicate the presence and differing amounts of both voltage and current, depending on its being in parallel or series. It also is used to indicate current due to Induction. Because the experience and language of series and parallel is introduced by and/or circuits, we can use the meter in series to use the term amp and in parallel to use the term volt.
The transformation, by Induction, of a moving magnetic field into a flowing electrical current is a key concrete experience of electricity.
6. Model and Language.
The model used to describe electricity is this. Like water through a tube, which we can show, electricity is pushed by a battery (or other source like a solar cell) through a wire and connected components. This circuit determines how hard it is to push. The battery and circuit together determine how much electricity gets pushed.
So, voltage becomes how hard you push. The unit name is Volt. Resistance is how hard it is to push. The unit name is Ohm. Current is how much gets pushed, through the (closed) circuit. The unit name is Amp. Fortunately these are monosyllabic phonetic terms, like cat and dog, and can be taught as such. They can also be expressed or characterized through hand gestures. Think, The Itsy-Bitsy Spider meets Tesla.
We also have the basis for the special meanings of the terms open and closed. Just open a simple circuit and see that no current flows then close it. Indicate that the electricity can move from one end of the battery all the way to the other only in a closed circuit. Demonstrate that opening and closing are what a switch does.
Current, being a movement, a flow, has direction. This idea gives rise to the ideas of direct current and polarity. It gives the chance to name and demonstrate the idea of current as also capable of going back and forth, pushing and pulling. This is alternating current. It can be presented with a straw. Blow out long one way and that is called direct and positive. Draw in long the other way and you have direct and negative. Puff back and forth and you have an alternating current. Literally, by the way. This is not a model of an alternating current. It is a real alternating current in a fluid medium.
The use of all these terms expands the child’s vocabulary and makes it possible to have conversations about the simple reality of electricity in the primary classroom. But where is this going?
Electricity’s three part equation.
We put the concrete experiences of electricity, the vocabulary and the idea of quantity into the prepared environment. At some subsequent point the older student will become comfortable with multiplication and division. Then we can point out that there is a mathematical relationship between how hard you push, how hard it is to push and how much gets pushed. That is,
Current = Voltage/Resistance
This is Ohm’s Law. It is one of a set of three part equations, speed=distance/time for another instance, that describe physical reality and belong to elementary childhood but are based in early childhood experience and language. It does not have to wait for high school.
