Observations of Mice, Err Students, in Lab
We’re now slightly past the halfway point in the semester. In fact, today is Fall Break. Students are given the day off before starting the push into finals (or more realistically the push to Thanksgiving break). In Astro 101 we just had our second exam, which I guess I’m justified to actually call a midterm. We’ve also completed about half of the labs for the semester. It’s this second milestone that I want to comment on.
Labs had been going smoothly until we reached the most recent laboratory exercise. I’m not completely sure what happened but there was just short of a mutiny when I assigned students the task of calculating Jupiter’s mass.
To give context to the problem let me first make some comments. At Coastal Carolina we teach Astro 101 using the SCALE-UP model. In the SCALE-UP approach, students meet three times a week for two hours at a time, as opposed to meeting three times a week for an hour and having a separate three hour lab at a different time. The SCALE-UP model allows us to complete labs at the exact moment the lecture material dictates. To maximize the idea that the labs are meant to address and reinforce difficult concepts, the labs have been written in-house with the student learning objectives for the course as guides.
Now to the problem with the most recent lab. So far the five labs we’ve completed are
Lab 1 – Introduction to Starry Night™: In this lab students played around with the planetarium program Starry Night™. During the lab students investigate a number of common misconceptions about astronomy, such as the uniqueness of the North Star, what really is the zodiac, and the fact that the Moon can be above the horizon during daylight hours.
Lab 2 – The Celestial Sphere: For this lab students are given a celestial sphere globe and asked to explore such concepts as the diurnal and annual motion of stars, the seasons, and what it’s like to live above the arctic circle.
Lab 3 – Solar and Lunar Motions: To study solar and lunar motions a 150 watt lightbulb is placed in the middle of the room to represent the Sun. Students are given earth globes and styrofoam balls (which represent the Moon) and are asked to study the effects of the seasons, lunar phases, and eclipses.
Lab 4 – Kepler’s Laws: This lab explores each of Kepler’s Three Laws of Planetary Motion, one after another. For example, students are asked to draw and compare ellipses of various eccentricities and semi-major axes; calculate the swept out areas over different portions of a planetary orbit; and verify that the eight planets do in fact obey the Third Law.
Lab 5 – Measuring the Mass of Jupiter: For this lab students are guided through the process by which astronomers measure the mass of a celestial object. Specifically, in the lab we use the orbital properties of the Galilean moons to measure the mass of Jupiter.
One of these labs is not like the others. The structure for the first four labs was to use a central theme, or set of laws, to explore a variety of concepts. In Lab 5, however, the task was to do one thing, measure the mass of Jupiter.
In writing Lab 5, I tried to break the measuring process into smaller, bite-sized steps. Nonetheless, the process still required a set of sequential steps to achieve one end goal. Along the way students ran into difficulties, such as realizing the sum of Jupiter’s mass plus the mass of any of its moons is, to a very strong approximation, just the mass of Jupiter.
Based on my observations of students completing the exercise and post-lab discussions with students, I think the overall ill will toward the lab arose because the lab required a dependent sequence of tasks. If students became confused at any point along the way they would become frustrated and would in turn get less out of the lab. In the other labs, the modulated approach meant that if a particular section was confusing, a positive outcome could still be attained through the other, less confusing sections.
This is only my hypothesis but it’s an interesting question. Should we, as educators, task our students to complete smaller, modulated labs or is it acceptable to expect them to complete a long lab with one central goal?
The answer to this question is not trivial. In many ways it depends on the audience. For a science majors class, such as a calculus-based physics, it may be acceptable. In these classes we want to instill in students the process by which scientists poise a question, and address the question through a designed experiment. For a class of non-science majors, like Astro 101, maybe the modulated approach is better. Here, at least in the style of labs I’ve elected to adopt, the goal of the labs is to support the lecture material through an emphasis on and a thorough analysis of difficult concepts. The goal is not to design or replicate a traditional experiment.
It would be interesting to investigate the different approaches to see if one approach versus the other create greater gains in a laboratory course.