In this lesson, students will circuitry materials to perform a lab to discover the relationship between resistance and current. They will need to think about and discuss what their variables will be, what tools they will use to measure them, and how many times to change the independent variable to measure the dependent variable. They will also need to think about what to control, and how to communicate their data once they have a data table.
Students often come to physics with a misconception that "3 trials is enough." This is largely due to experiences they may have had in biology and chemistry, where lab resources may be expensive, limited, and hard to come by. It is quite common for a biology or chemistry teacher to limit investigations to 3 trials simply to help them see a change in data with a limited amount of resources.
In physics, students often have fewer limitations on resources. In this lab investigation, aim to provide each group with at least five different resistors. More would be better. This way students will have to decide how many trials is "enough" to be confident about their data. Teachers should encourage students to put their data into a graph as a means of communicating whatever relationship they find. If they do this, then they will need to come to the conclusion that 3 data points is not enough to create a graph with a defined shape. They will need to change and measure the variables more than 3 times.
Note: You may need to review with your students how to tell the resistance of each resistor based on the colored bands, if the resistors you are providing have colored bands. This link might help: https://www.wikihow.com/Read-Axial-Lead-Resistors
Next Generation Science Standards
- Engineering, Technology, Applications of Science
- Physical Science
- NGSS Crosscutting Concept
- NGSS Practice
Computational Thinking in STEM
- Data Practices
- Modeling and Simulation Practices
- Computational Problem Solving Practices