Because I want my students to make connections to their prior knowledge, I begin this lesson by asking students to name and describe places where they have seen or used a switch to control electricity. Common answers include light switches, power buttons on televisions or video game systems, and nightlights. I record the students' responses on a chart and display it in the front of the classroom.
I then ask students to work in their table groups to make a hypothesis about how switches control electricity. I ask each group to come to a consensus and to record their hypothesis on a sentence strip. I display the sentence strips on the board so that students can revisit their hypotheses at the conclusion of the lesson.
I model the construction of a circuit tester and switch for the students. Students will use a circuit tester in subsequent lessons so I want to ensure that they can correctly construct a circuit tester and that they have the opportunity to ask questions about the process and product. I encourage students to take notes on the process of building the circuit tester in their lab notebooks.
After seeing the circuit tester and switch construction process, I provide students with the time to build their own switch and circuit tester. As they build, I ask students to record their observations on their switch lab worksheet. After completing the switch and tester, students diagram their completed circuit. A video of a student constructing a switch can be found here.
Once they have built their circuit tester and switch, I ask students to explore the materials and to make judgments about how electricity moves in the circuit. I want students to gain this knowledge through exploration, so I purposefully avoid telling the students any information about how the presence of a switch can impact the circuit. Instead, I ask guiding questions to lead students to the understanding that the switch controls the flow of electricity by completing or breaking the flow of electrons in the circuit.
I close this lesson with a formative assessment. Since the students are half-way through the electricity unit, I want to ensure that each student can diagram a circuit and describe the movement of electricity in a circuit. I use the switch exit ticket as a quick check for understanding.