Students design and refine oscillation experiments with plucked rulers, centering scientific integrity, bias mitigation, statistical comparison, and peer presentation of findings.
In this two-week lab sequence for introductory physics, student teams investigate the factors that affect the period of oscillation of a ruler clamped to a table and plucked like a diving board. Students choose their own variable (overhang length, material, mass, etc.) and design experiments to determine whether and how it affects the period. Using photogates with pendulum timing, they collect data, refine their methods, and apply statistical comparisons including t′ tests to evaluate their results. A central thread is scientific integrity: students identify sources of bias, develop practical strategies for mitigating it, and reflect on how bias influences experimental decisions. In the second week, students improve their experiments, expand the scope of their investigations, and deliver short oral presentations to peers, practicing the communication of experimental design, analysis, and findings. The lab builds skills in prediction-making, uncertainty analysis, iterative experimental design, fair testing, and collaborative knowledge-building, while centering the role of integrity and transparency in the scientific process.
Session 1 & 2:
Make predictions about expected measurements and use the predictions to check whether data make sense
When data and results do not come out as expected:
determine and test plausible explanations for the disagreement
test whether the results are reproducible under similar conditions
test whether the results are reproducible with improved precision
expand the scope of the experiment to look for “new” physics
When data and results do come out as expected, test whether the results are reproducible with improved precision
Consider issues of scientific integrity when conducting experiments and analyzing data
Experimentation Goals
These experimentation goals are most strongly represented in the explicit learning goals described above:
Student Decision Making
In this lab, students have the opportunity to:
Discovery
Determine results previously known to:
Duration
2 sessions of 2-3 hours/session
Equipment Required
Implementation Tips
Students use photogates with pendulum timing mode on LabQuest interfaces to measure the period of a ruler clamped to a table and plucked. The photogates offer very high precision, so there's little value in many repeated trials at a single overhang length — instead, push students to collect data at many different lengths or conditions. The lab doesn't fill the full session on its own, so press groups to gather ample data and begin planning a second experiment for the following week.
Students should have a working experiment with rough initial analysis done by the end of the first session. Remind them that most experimental designs don't survive first contact with the equipment, so early testing matters.
For the second week, calculate presentation time in advance (about 3 minutes per group plus transitions) and communicate a clear cutoff for when experiments must wrap up. Presentations are informal — no slides, just explanation — with all group members participating.
The scoring rubric can be treated as an interim score in the first week, replaced by the second week's score if it improves. This gives students two full weeks to meet the goals without the pressure of two separate deadlines.
A makeup option for absent students: provide them with data sets from multiple groups and have them calculate and interpret t′ for various combinations, identifying which data best addresses whether the chosen factor affects the period. Expect about two hours for this analysis.
How This Fits in Your Course
This is the fourth and fifth lab in a ten-lab introductory physics sequence focused on waves, oscillations, and sound. It follows three weeks of spring experiments (Springs 1–3) where students develop foundational skills in data collection, uncertainty, comparing data sets, and identifying relationships between variables. By this point students should be comfortable with basic statistical comparisons and have encountered the distinction between objective measurement and subjective interpretation.
The rulers unit introduces scientific integrity and bias mitigation as new themes layered on top of those existing skills. It also serves as the first experience with student-directed experimental design, where groups choose their own variable and methodology.
After this unit, students move to a Tones lab investigating sound, then to a multi-week independent investigation project where they formulate their own research questions and present findings. The mini-presentations at the end of the rulers unit serve as deliberate preparation for those later formal presentations. The follow-up homework asks students to begin brainstorming testable questions for the independent project.
2026-02 (Sp) Lab schedule.docx
Other12 KBLab
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Rachel Scherr
Lauren Bauman
Adrian Madsen
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