Science is about experimentation, creativity, even play. The greatest breakthroughs have come from those who pushed the known limits to ask why, how, and ultimately what if. If this is how the best science is done, then why don’t we start giving students autonomy to explore and create in the lab early in their university training? If we do, Natasha G. Holmes, Physics, says that perhaps they’ll get a taste of what it means to be a scientist early enough that they’ll choose science as a career path.
Holmes studies the teaching and learning of physics, especially in lab courses, but her work is applicable more broadly across many disciplines. “In the lab students have their hands on the equipment,” she says. “I’m looking at what they are getting or not getting out of that experience and also digging into what the lab space is actually good for. As a loftier, long-term goal, how can we provide students with transferable skills that will make them critical thinkers and good citizens?”
A Tool for Assessing Critical Thinking Skills in Physics
To shed light on those questions, Holmes is working on a project funded by the National Science Foundation to design a tool that can assess critical thinking. “This will be a closed response standardized test that allows any instructor to measure whether their students can think critically about a physics experiment,” Holmes says.
Holmes and her coresearcher, Carl Wieman of Stanford University, began designing the assessment by gathering initial data from respondents at multiple universities. They asked them a series of open-ended questions about an introductory level mass-on-a-spring physics experiment conducted by a hypothetical group of people. Respondents answered questions about the hypothetical group’s methods and the data that the group collected. For instance, they were asked if they thought the data collected was reasonable, how well they felt the hypothetical group designed the experiment, and how well the group evaluated the model.
“We were looking for the most common answers an introductory physics student would give,” Holmes explains. “But we also wanted to collect as many responses as we could from advanced physics majors, professors, and grad students to see the full spectrum of possible answers.” The researchers distilled the open-ended answers down into a multiple-choice test that can be given to students before they take a lab course and again afterward, to see how well they have learned the concepts.
Holmes and Wieman are still working on the third step in the process: scoring the test. Figuring out how to do that is complicated, Holmes says. “What are the right answers to these sorts of questions? With thinking and reasoning, there are lots of possible ways to go. We are trying for a range of rightness in the possible answers so that scoring can be based on how well-aligned a student is with what an expert would say.”
“In the lab students have their hands on the equipment. I’m looking at what they are getting or not getting out of that experience and also digging into what the lab space is actually good for.”
Do Introductory Physics Labs Function as They Should?
While creating the assessment tool, Holmes is also pursuing other projects that look at how well physics labs meet the goals they were originally designed to meet. As part of that work, she is the principle investigator of a new project funded by an Active Learning Initiative Grant the Cornell Physics Department received from the College of Arts and Sciences. Over the next four years, she will be reviewing all of the lab courses for two of the introductory physics sequences at Cornell. “The research we’ve been doing at other institutions has shown us that labs can be beneficial for teaching things like experimental design and understanding data,” she says. “Often, however, labs are used to reinforce physics content presented in lectures. Our findings have consistently shown that these labs are not meeting their design goals. They don’t help above and beyond seeing the information in lecture and discussion sections. That is one of our findings we will be seeking to confirm here at Cornell.”
In addition to assessing Cornell’s introductory physics labs, Holmes will apply another aspect of her research: designing lab courses that provide improved instruction on critical thinking, experimentation, and scientific reasoning. The courses she’s designed at other universities have put an emphasis not only on understanding and analyzing data but also on models. “The equations in physics that we talk about as describing the natural world are all just approximations and estimates,” Holmes says, “so they’re not perfect. It’s possible to collect data and show when these approximations break down and then begin to figure out ways to improve the models. That’s a big focus in the instruction we’ve been providing.”
Holmes’s lab courses are designed to allow students to play in the lab—to think creatively and to push the limits of what they’ve learned. “Students have this belief that they can’t go beyond the laws of physics. They can’t prove things wrong,” Holmes says. “They need to understand that the text book is not the absolute truth. It’s a pretty good description, but the point of experiments is to push the limits, to figure out what else we can know.”
To Feel Like a Scientist
In Holmes’ new lab design, students do experiments such as measuring the period of a pendulum. The equation the students learn in lecture class says that it doesn’t matter at what point in the swing the pendulum is released, the time it takes to make a full pass will remain the same. Once in the lab, students quickly confirm the prediction. However, the researchers push them to improve their initial data’s quality, to figure out ways to get better measurements, Holmes says. “As students’ measurements become more precise, they begin to see there are differences in the pendulum’s period depending on where you launch it. Ultimately they get to the point where they—as students, using a stop watch—have been able to push the limits of an equation they’ve seen in class.”
Students have a better appreciation for the nature of science after taking one of the labs designed by Holmes. In post-lab interviews, some have even described feeling like a scientist in the lab space. “That is remarkable,” Holmes says. “They weren’t just students they were doing science.” The benefits of that sort of experience can carry over into other aspects of students’ lives and can even change the course of their education. “When students do something like undergrad physics research, they have a revolutionary experience. It changes their whole perspective on physics, and it can convince them they want to go into science,” Holmes says. “There’s no reason we can’t be giving students that experience early on in these introductory labs.”