Science 9 – Students looked at how adding more bulbs in series affects the current of the circuit. They figured this out quite well. They then were given a reading and a worksheet to apply their new knowledge.
We went through the reading quickly and I pointed out to the students the parts where they should focus their attention. I think some type of homework/reading quiz may be needed in the future to ensure that students review their readings.
Science 9 – Students used compasses and charging/discharging circuits to see where current flowed in a circuit. This is a crucial lab to show that charges don’t originate in batteries. Evidence for this is that charge flows on both sides of the capacitor and charges can’t get past the insulator in the capacitor. As well, there is current when the circuit discharges without a battery.
This is such a great lab to do but it requires the right classroom culture. Students have to want to find answers to the questions being asked of them.
– The above video is me going over a lab that the students had already performed. Sometimes I go over them again quickly to make sure we all have the same consensus on what happened.
Using capacitors in high school science in BC generally is not done. However, we are using them not to learn about time variant current characteristics, but to analyze the nature of charges in a circuit.
The insulator in the capacitor breaks our original model of complete circuits. We get a working circuit, yet we know that charges aren’t crossing through the capacitor. As well, a discharging circuit will light a bulb, so charges can’t originate from the battery. In fact, as shown in the video we must be able to reason that charges are everywhere in the circuit because the compass rotates in all parts of the circuit no matter where the capacitor is.
There is a lot more to say about this topic, but that’s the general idea. These are great activities for the students because it challenges them to reason through logical inferences. Fantastic!
Science 9 – My science 9 students are now working with circuits in the electricity unit. I’m following my own modified version of the CASTLE curriculum. The first step for the students is to identify what materials are conductors and insulators, and to use some type of circuit setup to test for conductivity (battery, three wires, and a light bulb).
After today students have the model that a continuous loop of conductors makes a circuit while an insulator will prevent a circuit from working. In a few days we will try to break this model!