Sunday, February 28, 2010

Pondering the Question: "Why do physics labs?"

It's not a question that I lay awake thinking about before I go to bed at night. There are some questions like that, but this certainly isn't one of them. It is however a question which occupies my mind as I drive home from school or walk back to my office after a dreadful experience in the physics lab. Why is it that we do physics labs? What role does the laboratory play in our high school physics classrooms? Would our classes be any worse or better if we did less labs or even no labs at all? What value is there in the several hours of lab work which my students invest in during their physics course?

I did not ponder these questions during the first few years of teaching. I was taught during my teacher training days that students learn with their hands. So my conviction was if that is how students learn, then I ought to be doing labs. And it follows that the more labs I did, the more learning that will occur. No more questions asked. I tried to do as many labs as I could.

Now I know better. Students don't learn with their hands. They learn with their brains. There is nothing about the anatomy of the hand that allows the hand to acquire information, process information, evaluate information, etc. The brain is the center of learning. And if a particular lab fails to cause activity in the brain, then that lab will contribute little to nothing to students' ability to learn physics.

So the question arises again: Why is it that our profession believes in the practice of doing labs in physics class? Physics labs are a lot of work to set up. Labs are a lot of work to grade. Labs take class time and class time is valuable. So why do physics labs?

For several years I focused much energy and effort on making better labs. In my mind, I defined a better lab as a lab that made a stronger contribution to student learning. I tried many things to better my labs, such as:  Including less directions. Including no directions. Including more directions. Including better directions. Including better post-lab analysis sections. Including pre-lab analysis sections. Altering the equipment. Using computers as data collection tools. Trying new labs altogether. Trying more new labs. Etc. Etc. Through a whole lot of energy and effort, I was able to make some gains ... but very minimal gains ... hardly noticeable gains ... at times even negligible gains. The main fruit of my toil was that there are now more labs in the graveyard of my computer files than there are labs which are actually being used with my students. I was still left with the overwhelming sense that students learned very little physics through my physics labs. And sadly, student survey information seemed to verify the fact that for many students, physics labs did not live up to their promise of helping students understand physics concepts and principles any better than time spent in the front of the room. So again I ask: why do physics labs?

Only recently have I learned to look at lab in a new light. I have begun to ponder the possibility that labs are not solely about learning physics - at least not if learning physics means acquiring more knowledge of the topic. Labs are primarily about learning science - learning how to do science in the way that scientists do science. Labs are about the process, not about the product. The important learning that occurs from a lab occurs during the process of doing it, not as the product of doing it.  By doing lab, students learn about experimentation, control of variables, scientific inquiry, and the necessity of careful measurement. By doing labs, students practice skills of analyzing data and presenting arguments based on data. By doing labs, students learn that conclusions are based on evidence. By doing labs, students learn the types of things that cannot be learned when sitting in the front the room and or burying the nose in the textbook.

In my new way of thinking, I am tempted to ask: What does it matter if the three labs which I do during the Newton's Laws of Motion unit contribute very little to student understanding of Newton's law? For certain, as long as I am doing three labs during the Newton's Laws unit, I hope that they contribute as much as possible to students' understanding of Newton's laws.  Given the large quantities of time which my students spend in lab, I would never dare divorce lab from the curricular objectives. But what matters most is not what my students learn about Newton's laws, but rather what they learn about doing lab. What matters most is that the three labs provide students an opportunity to apply principles of scientific inquiry in order to answer a testable question. Through lab experiences, students should become better doers of science. They should become better experimenters, more skilled in the habits of scientific inquiry, and more practiced at collecting, analyzing, interpreting, and presenting data. And by becoming better at these tasks, students are becoming better at science ... that is, better at doing science.

It is the experience of doing lab which is important, not the content knowledge which is acquired as the result of doing a lab. The power of the lab is in the act of doing it.  The power is in the process, not in the product. I have no doubt: labs can contribute to learning a physics concepts better. And just as importantly, labs can provide students with a hands-on, experiential event to which I can refer as I introduce or discuss concepts in class. But even if labs didn't do this, a good lab is still worth doing by virtue of the fact that it gives students an opportunity to do science - to explore, to inquire, to investigate, and to collect, analyze, interpret and present data. Labs are worth doing because they are labs. And the best labs are the labs which get students engaged in the process of doing science.

The Lab is what makes a science course a science course. Without it, we might as well call our courses Natural Philosophy, The Mathematics of Physics, or Another Body of Scientific Knowledge.  But because there is a Laboratory in the back of the room, and because we demand that our students use that space to explore scientific questions, we can call our courses Science courses.

So these days I am feeling more comfortable with one of my questions.  The why do physics labs? question occupies less attention than it once did; it has moved towards the background.  But other questions have emerged to the foreground of my mind. The question I've been most occupied with lately is how do I get my students engaged in and invested in this process?  How can my hands on activities become minds on activities and not just merely recess from seat work? What are the features of physics labs that engage the Delilahs of my class?

Stop back soon for the rest of the story ... .  Or if you have some ideas of your own, click on the Comments link below and please share.

This week's article is contributed by Tom Henderson. 

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