Phys 131, Fall 2012 TA GUIDE—Lab 1, Part 1

Lab 1(Part 1)—Introduction to Excel and Analysis of 1-D Motion

Overview:

This is the first week of a two-week lab sequence designed to introduce the students to Excel and ImageJ (next week). To introduce them to Excel, they will be asked to analyze the 1-D motion of a cell from stop-motion images. The lab handout will give explicit instructions on the operation of Excel, but no guidance in the performance of the physics skill goals. Your tasks are: 1) to demonstrate Excel skills when asked and 2) to act as a guide for the physics skills (see the document on helping student groups learn). Though this is the first lab, they have had several weeks of class and should have the necessary theoretical background to investigate the cell’s motion. (It is often a good idea to put the approximate timing on the board, as well as a short list of the objectives/skill goals—see the next page.) (Students read the Intro to SCL doc in week 0.)

Materials:

• 2 per group—Outline: 1 shot/3 mins, scale provided, movement of the amoeba Dictyostelium discoideum

• 1 per person—Excel instructions/lab guide (written assuming no Excel experience)

Introduction:

• Groups of four students—but not performing in the Community Lab roles for this lab

• Show videos/mention next week’s task to motivate today’s measurement/quantification

• Briefly review the Skill Goals (Physics and Excel, on the next page)

• Remind students that they are ALL expected to master the skills, so they should take turns and help each other out. Taking notes may not be a bad idea, either.

• Inform students that a single set of position, velocity, and acceleration graphs will be collected from each group at the end of the lab today.

Summation/Submission:

• Recap the Skill Goals, clarifying any remaining confusion about physics concepts

• Discuss the challenges and considerations with the class, if any have not yet been addressed. Ask the students what they found most difficult/challenging about either the Excel or the 1-D motion analysis.

• Collect the set of graphs from each group (make sure that the group members have written all their names on at least one page, staple the graphs together). These should be reviewed by you for completeness/accuracy/conventional structure. Good feedback now will save you time later.

Phys 131, Fall 2012 TA GUIDE—Lab 1(cont.)

Excel Skill Goals:

• Enter data (clear column headings w/ units)

• Generate columns of data from a formula, learn to reference specific columns and specific cells

• Generate graphs (scatter plots)—what quantity gets plotted where? (Review dependent and independent variables.) How is it titled? How is it labeled?

• Adding a trendline (line of best fit) to a graph—do you force the origin? (Never!) Do you display the equation? (Always!) What does the R^2 (correlation coefficient) really mean?

• Adding error bars (uncertainties) to the data points on the graph (at least y vs. t)—how can we determine uncertainty? Is it the same for all data points? Do we have uncertainty in both plotted quantities (vertical and horizontal)? (Future Lab Skill Goal: How do we propagate uncertainty into calculated quantities?—A good question to present to lab groups that finish quickly. Another good task is the * above.)

• Introduce other cool tools: Sum, Average, Standard Deviation

Approximate Timing:(2 hours)

• Introduction: 15 minutes

• Data Collection: 25 minutes

• Data Entry/Data Table: 25 minutes

• Data Analysis/Graphs: 35 minutes

• Class Discussion/Summation: 20 minutes