Lesson: Discovering Ohm’s Law Student teacher: Kira Bonk Learning Context This lesson occurs in the middle of a high school physics unit about basic circuits. Students will be working in pairs with laptops, creating graphs of provided data. The goal is for students to derive the relationship between current, voltage, and resistance, otherwise known as Ohm’s Law. They are comfortable using Excel to generate graphs as they use it for most labs. Instruction is guided by the modeling curriculum used at Willowbrook High School. Learner Characteristics The class is composed of juniors and seniors, with more males than females. Students are respectful and generally well­mannered. The class can get talkative and wander off topic but there are no major behavioral issues. Instructions must be presented clearly and repeated several times. Overall, the atmosphere of the room is usually light­hearted. Learner Objectives ● Content By the end of the lesson, students should be able to: ○ identify independent, dependent, and control variables ○ use Excel to graph collected data ○ interpret graphs in order to discover the relationship between current and voltage, in addition to the relationship between current and resistance ○ determine the meaning of the slopes of their graphs ○ derive the equation for Ohm’s Law, V= I*R ● Process and Reasoning General Outline: ➔ Bell ringer ➔ Discuss Ohm’s Law activity briefly ➔ If laptops aren’t ready, continue to introduce upcoming lab ➔ Students have time to finish Ohm’s Law activity by end of class, then work on homework or start lab depending on the available time (it depends on technology) As students enter the classroom, they will be instructed to open the laptops and log on. When class starts, I will briefly discuss the bell ringer. Immediately after, I will tell students the agenda for the day: finish the Discovering Ohm’s Law activity and, if time permits, begin a lab that continues their exploration of circuits. Before discussing the Ohm’s Law activity, I will inform students that they have homework due Friday. The problems will already be written on the board. While I hand out the homework, I will begin the discussion about the activity. The purpose of this is to remind students of variables and allow the laptops time to log on, as it takes ten minutes sometimes. A student will be asked to go to the front whiteboard and draw a circuit. I will ask the class what the variables are, then another student will go to the board to draw the circuit for the second half of the activity. Variables will be discussed again so that everyone knows where the data they were provided with came from. On the board, I will list what is expected from students before they leave: a printed table, a printed graph, the relationship between the independent and dependent variables, an equation relating the variables, and answers to the questions on their sheet. Students will collect data and use Excel to create graphs. Then, they will analyze the graph to derive the equation for Ohm’s Law. Note: if the laptops are still not loaded by this time, I will introduce the lab they will be starting once they are done with the Discovering Ohm’s Law activity. I will have a student draw a circuit on the board, then I will explain what a power source is and go through the expectations for what is required in the lab write­up, which they should be familiar with by this point in the school year. If the laptops are loaded and ready to go, students will have the remaining time to finish the activity. If they finish early, they can work on the homework due Friday or begin the lab, depending on how much time is left. Assessment ● Pre­assessment The bell ringer will give me insight into how comfortable students are connecting voltmeters and ammeters in a circuit. The opening discussion of the activity will assess what they know about independent and dependent variables. I know from their previous work that they are fine with using Excel and should be able to fix the graphs on their own. ● Formative The formative assessment for this lesson is what they will be turning in at the end of class: their completed activity sheet, including the tables and graphs, the equation they derive, and the relationship between variables. Instructional Strategies, Materials and Technology ● Teaching Strategies My teaching strategies in this lesson are direct instruction and monitoring students as they work in pairs.While the laptops warm up, I will be discussing the Discovering Ohm’s Law activity with the intent of having them clarify what the variables are. Once the groups begin working, I will be monitoring their progress and answering questions. ● Materials and Technology ○ Whiteboard and markers in front of room ○ Class set of laptops ○ Discovering Ohm’s Law­ copies for class ○ Homework Packet­ copies for class At each lab table: ○ Power supply ○ Long and round light bulbs ○ Alligator clip wires ○ Ammeter ○ Voltmeter Possible Student Learning Challenges Students will be working in pairs and using laptops, so there are plenty of opportunities for them to avoid working. It will be important for me to keep students on track and make sure those students who don’t participate consistently are indeed learning.
A good number of the students are quiet, so I have to make sure I approach them because they may not ask for help. Observer Focus Are students actively engaged in relevant activities?