I am planning to start the year with a unit on electricity with my middle school students. I have never taught electricity before, and it is not my strongest science area, but it seems appropriate to begin with given the blackout this summer. My question is, what is the most logical way to organize the ideas? In other words, what is a good sequence for these and other sub-topics: -circuits - simple, series, parallel, switches, etc. -static charge -electromagnets -generating electricity Most textbooks seem to go from abstract (electrons) to concrete, but that is not how I learned to teach in grad school... finding a natural flow of activities is really challenging me. Please send me your ideas - what's worked for you?

-- Kelly Vaughan (kvaugha@nycboe.net), September 07, 2003

Answers

Subject: Electricity Unit - order of topics...

I would also recommend reading Rosalind Driver's (et.al) research into student's conceptions of science concepts. The book is titled "Making Sense of Secondary Science" and covers about every science topic imaginable and how students tend to understand the concept. The purpose of reading up on student conceptions is to try to avoid reinforcing or even introducing misconceptions. Plus, knowing where students tend to have difficulties will help in devising instructional strategies.

The classic starting point for an electricity unit of course is the challenge to light a bulb with a battery and a wire. This leads eventually to the idea of a simple closed circuit and developing mental models of electrical currrent. Aaccording to the research, that's where a lot of problems start. For example, students tend to think of current as a sequential process, where electricity travels from the battery to the bulb and back to the battery in sequential fashion. It might help instead to visualze current flow using a bicycle chain as analogy - each link in the bicycle chain influences the movement of the other links simultaneously.

Another caveat has to do with student's equating voltage with current: teach voltage first as a property of the battery, independent of current. The research also suggests you should avoid "measuring voltage distribution in a circuit on the grounds that it can lead to the idea that voltage is consumed."

Mike

-- Michael W Gatton (mgatton@vzavenue.net), September 24, 2003.

In the NTEN course I took last fall we started with a look at static electricity in the first week. We began with a simple demonstration (rubbing scotch tape). The demonstration opened the door to an explanation about electrons and charge. I think we then went on to study the simple circuit. We looked at the battery, current, and conductors and insulators. We made diagrams and we learned about switches and short circuits. In that second week we also were introduced to series and parallel circuits. In the third week we looked at volts and amps (and the voltmeter and ammeter). In the fourth week we studied resistance and I think potential difference. In the fifth week we were putting it all together. It wasn't until the end of the course that we looked at magnetism and electromagnetism.

The FOSS Magnetism and Electricity module starts with magnetism. It then moves onto circuits, switches, open and closed circuits, and then conductors and insulators. In the third investigation, students study series and parallel circuits. The last two investigations look at electromagnetism.

John Christiansen

-- John Christiansen (christiansenja@aol.com), September 24, 2003.