The past two days we started to look at series and parallel circuits through a guided lab that uses Play-Doh instead of wires. Play-Doh conducts electricity because of the high salt content. Just the idea that Play-Doh can carry a current engaged many students. Some didn’t believe it would work, others were just amazed.
The students worked through 5 circuits, following pictures to easily make the circuit, then writing down observations on the light bulbs in the circuit. They find that the light bulbs only light up if they bridge a gap in the Play-Doh wire (ie, there is no short). They learn that two lights in series aren’t very bright, but are then surprised when the two lights in parallel are both bright. Play-Doh allows shorts to easily be created by just taking another Play-Doh wire and tapping both sides of the light bulb. This was perhaps the richest part of the experience. Students had to reason why adding the alternative Play-Doh path turned the light off.
Overall I really like this lab because students can work through them at their own pace easily. Doing the task is simple, they just follow pictures. Writing observations is simple, they just write if the light is bright, dim, or off. Reasoning all of this is complex. For the reasoning they need to think like a scientist. I think the relative ease of completing the initial task helps students build momentum and confidence for the more difficult reasoning. Also, from the other circuits work, it seems like they enjoy puzzles and wondering. This activity is fun and they care about the answer because the lights turn on and off right in front of them without any kind of switch. It’s almost like magic.
In particular I’m happy with the progress of one student in this activity. I’ve had a student that shut down in all of his classes and just didn’t care about doing work, passing classes, or graduating. He’s a bright kid and used to ask many questions. He’s interested in science, and once taught the rest of his table the difference between a black hole and a worm hole. Recently I haven’t been able to get him to do any work, even with the recent engineering a bridge project. When the Play-Doh came out he was interested that it conducted electricity and helped make the circuits. I’m hoping I can continue to engage him in this topic through these hands on, puzzle-like tasks.