An exploration of spring systems: Asking and answering quantitative questions

This page is authored by Melissa Eblen-Zayas, Carleton College.
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This material was originally developed as part of the Carleton College Teaching Activity Collection
through its collaboration with the SERC Pedagogic Service.

Summary

Students are provided a context for exploration of springs and simple harmonic oscillators (a summer internship with a company that produces spring balances), and they must choose a question to explore that would be of interest to the company. While some possible questions are provided, no experimental directions are given. A variety of springs and lab equipment are available, and students must design an appropriate experiment to answer the chosen question. Students are asked to present their results in the form of a written memo to their supervisor at the spring balance company.

Learning Goals

  1. Gain experience designing experiments to test quantitative relationships, in this case related to springs and simply harmonic motion.
  2. Understand the limitations of experimental data based on experimental design and experimental uncertainties and/or understand the assumptions that are made in developing theoretical models.
  3. Where appropriate, gain skills in presenting data in graphical manner.
  4. Present experimental work in a concise, clear written format to an appropriate audience.
  5. Work cooperatively in groups.

Context for Use

This is a 4 hour lab for an introductory Newtonian mechanics course. Students will have been introduced to the simple harmonic oscillator and ideal spring systems during class prior to coming to lab. Students work in groups of three, and the memo is written as a group.

In order to allow students to be creative in their development of experimental design, a variety of different equipment is available to students include many different types of springs (varying in size, length, stiffness), Vernier dual-range force sensor, and air tracks with Vernier motion detectors and Logger pro software.

The memo is written as a group during the lab period. The instructor or lab assistant will read and discuss the results with each group before the end of the lab.

During the course of the 5 week course, students are asked to re-write one of the group writing assignments from lab, synthesizing information from lecture and the discussions with the group write-up. Thus the the group memo acts as a first draft of the assignment with the individual memo (if the student chooses to rewrite this lab) being a polished product.

Description and Teaching Materials

Below is the laboratory handout given to students:
Lab Hand-out (Microsoft Word 23kB Jun2 06)

A hand-out pertaining to the evaluation of the individual write-up. This is a set of general guidelines because students chose to write up individually one of the the three labs in which they have done a group write-up.
Evaluation (Microsoft Word 21kB Jun2 06)

Teaching Notes and Tips

On asking appropriate questions:

The most important aspect of making this lab successful is to make sure that students spend a significant amount thinking about the question they want to explore and how to design an appropriate experiment to carry out the exploration. I expect students to spend at least an hour exploring the equipment and developing a reasonable question.

I encourage students to begin by exploring the equipment that is available to them. Students frequently do not realize that what questions they can answer may be limited by the type of data they are able to collect. Once students have experimented with the available equipment, they are asked to decide what question they want to explore. Once students have clearly articulated the scope of their exploration, they must present their idea to either the instructor or the lab assistant.

On writing about the results:

In the previous labs, students have spent a significant amount of time discussing the value of graphical presentation of data. In this lab, I encourage them to continue to think about effective graphical presentation of their results.

I have found that students, while they have collected quantitative data, frequently fail to include quantitative elements in their written memos, writing instead, "The spring constants are largely similar" or "Hooke's law seems to hold for a large range of masses, but not for all masses." Encouraging students to include specific quantitative statements in their memos is important.

Assessment

Grading Rubric (Acrobat (PDF) 49kB Aug6 08)

References and Resources