DC Circuits: From Bulbs to I-V Curves (3-Week Lab Series)

Resist the urge to teach. The first activity — lighting a bulb with only a battery, bulb, and single wire — is designed for students to discover the requirements for a complete circuit through exploration. Don't tell them how; ask "What arrangements have you tried?" and "What else could you try?" They will find it, and the discovery is powerful.

Pacing is the main challenge. In Lab 1, students must reach circuit diagrams to stay on track; series/parallel can slide to Lab 2 if needed. In Lab 2, they must at least complete ammeter measurements; voltage can carry into Lab 3. Post a suggested schedule on the board each session.

For Lab 3, warn students to turn down the power supply if their bulb gets very bright — bulbs blow out easily. Have spare bulbs on hand.

The PhET Circuit Construction Kit DC (phet.colorado.edu) is used for homework and makeup assignments. For Lab 3 homework, use the "Lab" page with "Advanced" and "Add real bulbs" enabled so that simulated bulbs behave nonlinearly like physical ones.

A Desmos graphing template is provided for I-V curves and supports uncertainty bars and multiple trendline options. Students can also use Excel or another tool of their choice.

Strongly encourage students who miss Labs 1 or 2 to attend another section rather than doing a makeup, as hands-on circuit building is very difficult to replicate remotely. Lab 3 can be made up using another team's data to create the graph.

Have students use different font colors in their shared Google Doc so individual contributions are visible — this matters for grading the team agreement and assessing equitable participation.

This is the opening unit (Labs 1–3) of a 9-lab introductory physics lab sequence for introductory electricity and magnetism. No prior physics lab experience or circuits knowledge is assumed — students build concepts from scratch through observation.

The sequence is deliberately front-loaded with structured inquiry so that students develop foundational lab skills (team collaboration, lab notebooks, circuit building, multimeter use, uncertainty analysis, and scientific graphing) that they will need for the rest of the course. By the end of Lab 3, students should be comfortable building circuits, using measurement tools, and creating scientific graphs, including uncertainty.

The circuits unit is followed by Lab 4 (Electrostatics), Labs 5–6 (Magnets), and Labs 7–8 (student-designed investigations), culminating in Lab 9 (presentations). The skills developed here — particularly experimental design, uncertainty quantification, and graphing — are prerequisite for the open-ended investigation later in the quarter, where students choose their own research questions and design their own experiments.