To begin we are going review with elbow partners what we did when built a circuit. Students will turn and talk with their elbow partner reviewing how they got their light bulb to light. I ask them to use the word circuit as they explain what the did and learned. I have a student ask if they can use their science journal in order to talk about the circuit experiment. This is always a great idea. Students are beginning to use their notes to help them explain their learning. When one student begins to use their journal it creates a popular trend and many others begin to read from their own.
I pair students up into new pairs. I then have them get the materials they will need: battery, battery holder, light bulb and holder, two wires, and a switch. I do not call it a switch, I say blue thing because I want them to discover for themselves what the switch is.
I then ask the pairs to build the circuit we did the other day. This will mean that they will not use the switch. I then ask them to include the blue box. It is easy to tell where the wires connect and students figure out that the top metal piece moves. I ask them to try to figure out once the circuit is made what the blue thing is. This takes a few minutes but once two groups have it the class begins to understand what to do.
During this time, I walk around and monitor progress. I only offer help that does not give away anything.
With a class of working switches, we are ready to discuss the difference between an open and closed circuit. I ask that students get out their science journal and begin drawing the new circuit that they created. I have them clean up and keep one out as a model.
I draw my own picture of a circuit onto the board. I try to use the symbols that are often used to describe a circuit. I explain the circle with an X in it as the bulb and the parallel lines as the switch. I then ask the class to explain to me what happened when they moved the switch. I then explain the difference between an open and closed circuit. That when the light bulb was on, the circuit was closed, allowing the current to flow through. When we opened the circuit the switch made a break in the flow and the light could not come on. I then have them write their own definitions for the two into their journals.