Yesterday, the students worked on creating a circuit with a switch and one receiver. Today, I will ask them to consider, and discuss with their shoulder partner, "What would happen if there were two receivers in the circuit? How would you build that circuit?"
As the students discuss with their partners, I will listen to glean insight into their predictions and basic understandings of circuits. Listening to these conversations is critical, as it may set up, or change the direction, of the mini lesson. I will then prepare the students for today's exploration.
As in every lesson in this unit, I will begin by showing my students all of the components for this investigation on a tray. Nothing will be connected. They will have a battery, a light bulb in a holder, a switch, and I will place either more or fewer wires than necessary on each of the trays. This is to spark inquiry. Student teams will either need to decide to ask me for more wires to create a successful circuit, or eliminate wires they don't need.
Next, I will explain to the students that their charge is to build a circuit that will turn a light and a motor on with a switch. I do not alert them to the fact that each receiver will be less strong as it shares the power. I want this to be their finding and I am also hoping it produces conversation and problem solving.
This clip shows a student group working from a successful circuit with one receiver and trying to add a second. I needed to use some questioning to pull one student into the solution discussion. The sound is poor in part of this clip, but the boy responds that he thinks they may need another wire in order to connect to the battery.
This team did the same thing. They built a circuit with one receiver and then decided they would figure out how to connect the second receiver. Their model is not sequential, but it works, so I have them trace the flow of energy for me to be sure they understand what they built.
As this team tried to get their first receiver working, I found a mistake in their model and challenged them, rather than corrected them, to build it differently. Once they had their model built with only one wire from each component, I explained why electricians would do it this way. I like to suggest, or challenge, rather than "correct" their thinking.
This team was able to build a successful model and realized that the bulb was much more dim than when it was the only receiver in the circuit. Their conversation was interesting, as one student hypothesized that it was because the source was used before and was running out of energy. I was then able to ask a different question to consider.
As a closing today, I will ask students to write a journal entry about everything they know thus far about electrical circuits. In doing so, I will be able to assess their knowledge, gain insight for future mini lessons, create investigations, and use them as springboards for class conversations.