Lesson 7 of 10
Objective: Students will explore simple circuits and differentiate between series and parallel combinations.
During the previous lesson, students were introduced to Ohm's Law and the basic components of a circuit. The goal for today's lesson is to apply that understanding of circuitry and explore series and parallel resistor combinations (HS-PS3-5) in a lab activity. Specifically, students use wires, batteries, and light bulbs to construct simple circuits and then explore the difference between series and parallel circuits (SP3, SP4, SP6 & SP8). Class starts when students show what they know about circuits. This activity activates their prior knowledge and gets them ready for the lab activity. Today's lesson ends with a fish bowl closure.
Today's class starts off with students recalling what know about electricity - specifically Ohm's Law. I have the words "Ohm's Law" written on the front board and have students pick up a blank piece of paper as they enter the room. Once the bell has rung, I ask students to write down anything and everything they know about how voltage, current, and resistance are related. They should be working on this individually, without notes, as I'm using it as way to assess their knowledge.
Once a full five minutes has passed, I choose a student to share an idea from his paper. I usually pick the student closest to me, and after he's shared I write his idea down on that front board. We then go around the room and students continue to share, but once a contribution has been recorded it cannot be repeated. This process continues until all ideas have been shared. I leave it up to the individual student to decide if he wants to copy down what we are writing, but I do leave our example on the board in the hopes that we'll refer back to it throughout today's class.
While students are sharing their ideas, I am internalizing the information they are contributing. Looking at how much, or how little, they know helps me to adjust my pacing and depth for the entire unit. I'm also trying to identify any misconceptions that were shared so that I can be sure to address and correct those before we move into the circuit exploration lab.
Exploring Circuits Lab
The goal of this lab is to allow students to build simple circuits and practice drawing schematic diagrams. Students start by building a simple circuit with one bulb. Once they have a working circuit, students test objects from their backpacks and determine whether these objects are conductors or insulators. Then, they add a second bulb to the circuit and explore the difference between the colored wires contained in their kits. Finally, students explore series and parallel connections before writing a conclusion about their exploration experiences.
At this point in the year my students have formed deep relationships with each other, so I allow them freedom in choosing lab partners. Groups of three seem to work best for the lab so students can work together and problem solve effectively while recording data. After they've chosen their groups, someone from each group needs to get a copy of the lab and a circuit kit.
The procedure in the lab document is straight-forward, but students have not been formally introduced to the definition of "series" and "parallel". Because of this, the lab serves as an inquiry opportunity and requires students to use their text or the internet to differentiate between the two types of direct-current circuits. I make sure to circulate throughout the room and check-in with the groups as they are working. I offer feedback on how students are wiring their circuits or help them troubleshoot when a bulb isn't lighting. Students understand the expectation that as they are collecting data they should also be thinking about justifying any conclusions that they write. As I walk around, I might ask students to "Explain why your ID card acts as a conductor." or "Why does this bulb light and this one doesn't?"
When there is approximately 10 minutes prior to the end of class (5 minutes left of the time I've allowed for this activity), I ask students to put everything back the way they found it and return to their seats. I also tell them at this point that the lab is due at the start of the next class meeting.
A successfully completed lab should include photos (or drawings), concluding statements and observations for each section, and a comparison of series and parallel circuits. If there is one adjustment I could make to this lab, it would be the inclusion of schematic diagrams. The students did a fabulous job of showing me they are engaged and having fun, but I need to know they understand schematics.
Students are back at their desks after cleaning their lab stations, so now I pass around small slips of paper (about the size of a standard sticky note). Each student should take at least one of these slips of paper so they can participate in our fishbowl closure activity. I explain to my students that they need to write down one question that they'd like answered about the general concept of electricity or today's circuit exploration lab. Each student must write something down, fold the slip of paper in half, and place it in the fishbowl at the front of the room.
I keep the room pretty quiet for this closure, as I want students to really reflect on what information they are feeling unsure about. I also don't want students to all have the same question, which is more likely to happen if students are able to share. In the past I've noticed that students are sometimes too shy to ask questions, so this activity should give them confidence by being anonymous. And, I pass around the slips of paper instead of simply handing a student just one so that if they choose, a student can take more than one slip for multiple questions.
This is a pretty fun activity and I read and answer the questions during the next class period. I use just a stack of blank colored paper and chop it up with a paper cutter in the faculty lounge before class begins. I also use an actual fish bowl to make the name fit the activity, so that's empty and sitting on my desk at the start of class. And, to ensure all questions are appropriate and meaningful, I remind students of these requirements and read each slip of paper before going over them!