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. 

Labor Or Oratory

It's Wednesday morning and Delilah enters the classroom and asks "Are we doing a lab today, Mr. H?" I answer in the affirmative and she responds with an enthusiastic "Yes." Her question and response elicit a wealth of emotion inside of me as I continue preparations for the lab. Most of these emotions are negative. I am upset, disappointed, and feeling a sense of defeat.

You might be asking "How could a physics teacher be upset about a student's expression of enthusiasm for a lab?" The answer is easy. We are four months into the school year and by now I know that Delilah isn't excited about doing a lab. Rather, she is excited about being in the lab. She is excited about being in the lab where she can talk and not being in her seat where she must be still, attentive and quiet. She is not excited about pondering a question, devising a procedure, collecting data, analyzing data and completing a report. When it comes to doing those tasks, Delilah will definitely disappear into the background. And unfortunately, her presence in the lab group will likely draw one or two more members of the group into the background for off-task conversation and socialization. Delilah talks with a friend, allowing her partners to do most the work;  she joins them near the end of the lab to get their data and endures their efforts to analyze it.

Delilah's attitude towards lab is like a contagious infection that spreads to those with whom she has social contact with. This is the infection which can destroy a laboratory environment, transforming it from an environment of scientific inquiry into one of social inquiry. It is not the labor of the Laboratory that has Delilah excited on this Wednesday morning. It is the oratory of the Laboratory which has Delilah excited. And that explains in part why the negative emotions flush through my body on this Wednesday morning.

During the first days of the course, I make an effort to create the proper mindset towards the laboratory.   With as much drama as I can muster, I explain to students that ...

The laboratory is sacred. It is the place in the room in the room where you become engaged in the doing of science. The answers to scientific questions are found in the back of the room - in the laboratory. It is in the laboratory that you will be engaged in the most important activities in science - asking and answering a question through observation, measurement and data analysis.

Physics is not a spectator sport. You must be mentally active. Those who approach physics in passive mode will be less thrilled and most disappointed by the course. Physics involves involvement! It demands a proactive approach to learning. It demands pondering, thinking, problem-solving, inquiring. To be successful, you will have to both sort it all out ;and put it together. And the location in the room where you will be most on your own and most active will be in the laboratory. You won't be alone in the lab, but you will be on your own - on your own to ponder a question, to adopt an approach to answer it, to collect some data and to sort out the meaning of what the data says about the answer to the question. In this course, you will be quite active in the lab, involved in a question, pondering and thinking through the results, and determining the answer to the question. This is science and science happens in the lab.

I repeat the message throughout the first weeks of the course with the fervor of an evangelist. I tell stories, design experiences and emphasize the central role of lab in the course. And now four months into the course, it is evident that my view of the laboratory and Delilah's view of the laboratory clash. I view it as the Laboratory and she views it as the labOratory. It is the same place in the room, but the emphasis, the motives, the reason for going there and the type of pleasure which is derived from there are polar opposites. My laboratory is sacred sermon has not been received. In fact, it has been sacrilegiously trampled upon. The place in the room which I spent several weeks consecrating to the service of science has been profaned.  For Delilah, lab time has in effect become recess time. It is not a time in which she becomes engaged in the most important aspect of the course - doing science; rather it is a time in which she assumes she can exercise her right to avoid science.

The truth is that my message regarding the nature of the laboratory has not yet been received by all. There are more Delilahs out there - in my class room and probably in yours. Should we be surprised that a large percentage of our students do not share our passion towards the laboratory? It is the proverbial dilemma: you can lead a horse to water, but you can't make it drink.

But is this the end of the story?  Should we just throw in the towel, give up and let the Delilahs be Delilah? No!  Come back in a couple of weeks for ... the rest of the story.



This week's article is contributed by Tom Henderson. Tom is the author of The Physics Classroom website.  He is a graduate of the University of Illinois in Champaign-Urbana, Illinois. He has been a high school physics teacher since 1989. Tom currently teaches Honors ChemPhys (Physics portion) and Honors Chemistry at Glenbrook South High School in Glenview, IL, where he has taught since 1989. 

Improving Students' Scientific Literacy - ACT Season

It's ACT season again. Juniors (and in some instances, sophomores, freshman, etc.) across the country will be marching into test rooms to take a battery of tests, the outcome of which could effect their ability to get into the college of their choice. For many high school juniors, taking the ACT is an optional experience. For juniors in Illinois where I teach (and in other states), taking the ACT is not optional. It is part of the state-mandated testing program used to assess student achievement and the job which schools are doing to promote student achievement.

It may seem to a physics teacher that a 40-question science test has little to do with our teaching of science. But it does! The ACT publishes a collection of College Readiness Standards (CRS) for Science - standards upon which questions are based. The CRS (or curses, as a colleague of mine refers to them) are broken into three strands. The three strands of standards are:

• Interpretation of Data
• Scientific Investigation
• Evaluation of Models, Inferences and Experimental Results

As a physics teacher, those three strands have a lot to do with my teaching of physics. And most particularly, they have a lot to do with the implementation of my physics lab program.

If you give the College Readiness Standards a closer look, you will notice that they are great standards for your lab program. For instance, consider the following standards from the Interpretation of Data strand:

• Determine how the value of one variable changes as the value of another variable changes ... .
• Translate information into a table, graph or diagram.
• Identify and/or use a simple (e.g., linear) mathematical relationship between data.
• Identify and/or use a complex (e.g., nonlinear) mathematical relationship between data.
• Extrapolate from data points in a table or graph.

I would love my students to become more skilled at these types of activities as a result of participation in my lab program. By providing students with practice at developing these skills through lab activities and post-lab analysis sessions, I am nurturing better science students, but also preparing students for success on the ACT test.

Now let's take a look at some College Readiness Standards under the Scientific Investigation strand:

• Understand a simple experimental design.
• Understand a complex experimental design.
• Predict the results of an additional trial or measurement in an experiment.
• Identify an alternate method for testing a hypothesis.
• Predict how modifying the design or methods of an experiment will affect results.

Once more, these are great standards for a lab program. If my students could develop their understanding and skills in the areas of these standards, they would be much better lab students. And they would also perform better on the ACT test.

Finally, lets look at a few College Readiness Standards under the Evaluation of Models, Inferences and Experimental Results strand:

• Select a simple hypothesis, prediction or conclusion that is supported by a data presentation or a model.
• Determine whether given information supports or contradicts a hypothesis or conclusion, and why.
• Identify strengths or weaknesses in one or more models.
• Determine which model(s) is(are) strengthened or weakened by new information.
• Use new information to make a prediction based on a model.

We likely all agree that students need to improve their skills of thinking critically, analyzing information, designing experimental procedures, interpreting data, evaluating models in light of evidence, and drawing evidence-based conclusions. If my physics lab program (and other parts of my physics curriculum) were instrumental in improving these skills, then I would consider the lab program and supporting curriculum to be a success.

With confidence, I can say it's ACT season. Every day of the year, it should be ACT season in my physics classroom. Every day of the year, students should be improving their scientific literacy skills. It's ACT season again always.




This month's article is contributed by Tom Henderson. Tom is the author of The Physics Classroom website.  He is a graduate of the University of Illinois in Champaign-Urbana, Illinois. He has been a high school physics teacher since 1989. Tom currently teaches Honors ChemPhys (Physics portion) and Honors Chemistry at Glenbrook South High School in Glenview, IL, where he has taught since 1989.

Tom invites those teachers who are interested in providing physics students with practice at taking ACT test type items to view and even use the following documents as practice opportunities within the classroom:

• Research Summaries Passage: Head Injuries and Football
• Data Representation Passage: Ball-Bat Collisions