Day 123 – Bulbs in Parallel


Science 9 – Students continued with their circuits. Today’s results were really surprising to everyone.  By adding another bulb in parallel, the bulbs didn’t go dimmer!  This was a shock to everyone.  I tried to help them to understand what was happening by using an analogy of blowing through one small straw vs blowing through three small straws at once.  Unfortunately I didn’t actually have the straws and many kids thought three small straws would be harder to blow through.

Note to self: have a box of stir stick straws in class next year.

Day 121 – Bulbs in Series


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.

Day 117 – Capacitors in Circuits

Science 9 – 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!

Day 115 – Soldering Capacitors

Science 9 – I made a video for students so they could try out soldering. The end goal here is for students to solder capacitors back to back. I want the students to do this because easily purchased large capacitors are polarized. If a student hooks up a polarized capacitor backwards, it can get fried. By soldering them back to back, we get a non-polar capacitor. The capacitance drops according to 1/Ct = 1/C + 1/C but this drop is ok. And, students enjoy learning a new hands-on skill.

Day 106 – Circuits

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!

Day 96 – Electrostatics

Science 9 – Students made their own pseudo electroscopes today. It was mostly an exploratory activity. Students put two pieces of tape down on the desk, pull them off, and then put them on the straw holders. These pieces of tape then repel each other. However, the tape is attracted to almost every other object in the classroom that is an insulator. Why? I love this kind of challenge on their inductive reasoning. I’d like to think that it helps develop their reasoning and isn’t just a reflection of their innate reasoning at this point in their brain development.

Day 87 – Exit Slip

Science 9 – Trying hard not to get mired in smaller details of reproduction, students did some practice with small concept maps of sexual reproduction and slide show overview of asexual vs sexual reproduction. The class ended with my asking for an Exit Slip. As many teachers know, this is a great formative assessment tool.