It's (All) About Data

Lab: it's all about data. From beginning to end, the focus is in one manner or another on data. Scientists begin with a question that they hope to answer. And from then on, the focus is on data. And our physics students should participate in the same type of data-centered activities as those of scientists.  Here is a sampling of the type of data-centered activities which characterize most labs.

• Deciding on what data to collect. 
• Deciding how to gather the data. 
• Collecting the data. 
• Deciding how to record data. 
• Recording the data. 
• Determining what the data mean. 
• Determining if the data mean anything at all. 
• Evaluating the trustworthiness of the data. 
• Comparing the data with the data of other experimenters. 
• Comparing data with previous experiments. 
• Graphing the data. 
• Analyzing the data. 
• Presenting the data in various forms.  
• Deciding what forms would be best for presenting the data. 
• Drawing conclusions based on the data. 
• Collecting better data. 
• Deciding what new data to collect. 
• Deciding on better methods of collecting the data. 
• Using the data as evidence. 
• Referring to the data in support of conclusions.

Clearly labs are data-centered activities - activities in which a wealth of decisions about data must be made in order to pave a logical trail from the question to the answer.

It is at this point that science is distinctly different than the other disciplines which our students study. In many of the other disciplines, opinions prevail.  In science, data prevails (or at least should prevail).  As we all know, there is not a lot of room in science for opinion.  Scientists follow the data towards their logical conclusions and make every effort to build models which both assimilate the data and explain the data. In science classes, our students should be doing the same types of activities. They should be given an abundance of opportunities to collect, analyze, evaluate, and draw conclusions from the data.  When it comes to labs, its all about data.

An article titled Using Levels of Inquiry in the Science Classroom, written by Jeff Rylander, was posted previously on this blog. In his article, Jeff provided a framework for thinking about scientific inquiry lab activities.  The framework centered around the division of a lab task into the formulation of a testable question, the development of a method or procedure for answering the question, and the formulation of a solution or answer to the question.  In the framework presented by Jeff, higher levels of inquiry are characterized by activities in which students have a greater degree of control in the various stages of the lab task.  (Jeff's ideas regarding levels of inquiry originated from an article published in The Science Teacher by Michael E. Fay and Stacey Lowery Bretz. The article is available online at NSTA's Science Store.)

When I think about the centrality of data in a physics lab, I think about Jeff's article. Particularly, I think about the locus of control in the various data-oriented decisions which must be made during the course of a lab.  As an instructor, I need to be thinking about what data-related decisions students will be left to make. I need to think about whether I make the decision about what data they collect or whether they decide on what data must be collected.  I need to be thinking about whether I decide on the methods by which students will collect the data or if I will leave that decision to them.  I need to be thinking about whether I decide on how students will organize and present the data or if I will leave them to decide on this matter.  Consistent with Jeff's framework for levels of inquiry, the more the locus of control is shifted from the instructor to the student, the higher the level of inquiry which the lab will assume. And one way to think about scientific inquiry is to think about how many of the data-oriented decisions are being made by the instructor and how many are being made by the student.

As I write this article, I am one day into summer vacation.  School ended yesterday. The summer months allow time to relax and to rest (and to catch up on the honey-do lists), but also time to reflect, rethink and retool. For me, much of my summer reflections will be focused on how I can improve the scientific inquiry skills of my students.  And for starters, I will be thinking about the types of revisions which I can make to the lab program in order to foster improved inquiry skills.  I will be looking at the labs which my students do through the lens of data.  I will be pondering each lab which my students do and asking:  When it comes to data-oriented decisions, where is the locus of control for this particular lab activity? The more that the control lies upon the student side of the equation, the higher the level of scientific inquiry.

In Praise of Projects

In a previous blog, Debbie Berlin wrote about the end of semester projects used in her Regular Physics classes at Glenbrook South High School.  Inspired in part by the design and the success of that project, I decided to implement a similar project in one of my physics courses.  The course is called ChemPhys - a two-year course in which students take chemistry and physics on alternating days, thus completing a full year of chemistry and physics over the course of the two years.  The guidelines, expectations and scoring scheme for the project which I have implemented with my classes are described online at the course site (http://gbschemphys.com/chemphys/lab/project/project.html). In brief, I would describe the project as an open-ended experimental design project in which students attempt to identify and answer a testable question which is of interest to them.  There are few constraints in terms of topic, as long as physics is a naturally intrinsic part of the topic.  As I write, we are currently in the middle of the project, having completed a couple of days of planning and research and three days of experimental investigations.  I am offering in this post what is a sort of mid-term reflection of the progress, joys and frustrations which I have witnessed and experienced.

The most striking observation which I have made thus far is in the level of excitement which students have displayed. The project comes at the end of a two year course and in May - when the northern weather begins to turn bright and sunny and when the students have begun reducing the number of school days remaining to less than 20. This is not exactly a prime time for the display of academic enthusiasm.  Yet there have been several times when I have had to cheerfully pinch myself after being placed in a state of shock by an observation or comment.

The first day of lab research was originally scheduled to begin on Thursday, May 6.  For a variety of reasons I had decided to postpone the start of research until Monday, May 10.  One of the students in my second section of the day entered the classroom looking very dejected and down.  I asked her what was wrong.  She responded about how upset she was that the project had been postponed. She had heard from a friend in a previous section that it would not start until the following week.  She had commented how much she was looking forward to this day and how disappointing that the news was.  I was rather shocked that she was taking what seemed to me to be a very inconsequential decision as a very disappointing turn of events. I began to wonder: When was the last time that the postponement of an in-class activity caused such obvious disappointment on the part of one of my students?  I could not think of such an instance in my 20-plus years of teaching.  Clearly, this student possessed a sense of excitement and anticipation over the start of this research project.

On the third day of our lab research, I entered the room four minutes before class and was instantly struck by what I observed.  Several students had arrived before me and were in the back of the room setting up.  They were fetching their equipment from the various storage locations and preparing to start their research.  As other students entered the room, they set their bags down and headed to the back of the room to do the same.  There was no need for prompting or prodding. They knew what to do and didn't wait for an invitation to do it. With a minute prior to the start of class, one student entered the room, looked around, looked at me, and asked with a sense of amazement "Did the bell ring already?" Given the activity that she observed, she assumed that class must have already started and she had arrived tardy.  I assured her that she was on time, in fact one minute early, but there was no need to wait to begin.  Again, I began to wonder:  When was the last time that my students entered the room and spontaneously began to do science without any prodding or prompting?  Once more, I could not think of such an instance in my 20-plus years of teaching. Clearly, this research project increased the level of engagement of my students in the task of doing science.

A research project of this variety is an assessment.  It is a means of assessing student capability and performance in a manner in which a traditional test is unable to do so.  My tests excel at determining what students know and understand about the concepts and principles of science.  They are able to test students' ability to analyze complex physical situations and to solve physics word problems.  They are capable of determining the proficiency of students at analyzing diagrams and graphs.  But they are unable to test student's ability to conduct an experiment from beginning to end.  One role which this research project plays is that it assesses students' ability to do science: to design an experiment, to determine what data to collect and how to collect it, to analyze the data and draw conclusions, and to determine an effective manner to present the data and results.

As an assessment, a research project of this variety teaches me much which I might not otherwise be aware of.  For instance, it is clear to me that my students have great difficulty identifying a testable question.  During the brainstorming stage of the project, many of my students were able to identify great questions; yet very few of the questions that students initially proposed were testable.  Their questions reflected topics of interest and innate curiosity.  But their questions also reflected tremendous confusion regarding what constitutes a testable question.  Purpose statements such as "to determine what an unsafe speed is in a bobsled race" reveal great curiosity but not much understanding of what can and cannot be done via a high school physics lab experience.  I quickly recognized that the development of a testable question was indeed a challenge for students. I couldn't help but think of a previous article in this blog by Jeff Rylander on Using Levels of Inquiry in the Classroom. In that article, Jeff discussed a hierarchy of four levels of student inquiry which were based upon the work of Fay and Bretz. My research project was challenging students at the highest level - the level in which the question, the procedure and the solution is constructed by the student.

This research project was doing what any good assessment should do - providing the teacher an opportunity to assess student ability and know-how with the intent of affecting curriculum and instruction. Given the difficulties which I have observed, I am already making plans to incorporate more level 4 inquiry challenges into the course.  My goal will be to improve students' ability to construct the question, the procedure and the solution.

My final observation pertains to the dramatic change in my role as teacher.  This research project has truly put me in my rightful place as the guide on the side.  My role is no longer the sage on the stage; rather I am an advisor serving a similar role as a college professor guiding the research of a graduate student.  I suggest things to think about, offer alternative procedures, and direct students to experts in a field or exceptional resources. When the groups encounter difficulties, I become part of their brainstorming team;  together we ponder ideas for circumventing the road-block. I serve as a sounding board for those students who are thinking through what to study, how to study it, how to interpret data, etc.

In addition to being an advisor, I am also a lab equipment manager.  With 16 different projects happening at once, I must make sure that every lab group has what they need when the need it.  This means lots of planning and preparation.  There's no chance for spur of the moment, last-second planning and preparation.  Trips to the local hardware store are common.  These must be planned in advance of the start of the school day.  I certainly can't run out to the hardware store in the middle of class.


I have been pondering the topic of engagement over this past semester.  Exactly what is it that gets students engaged and invested in labwork?  What is that causes students to be excited about the back of the room? What gets students turned on about doing science? I must be honest that I don't know the answer. But one thing that I do know is that an open-ended challenge of this nature seems to maximize student interest and involvement. When students are responsible for the design and development of the entire investigation regarding a topic of their own choosing, the investment level increases. Students become true scientists, engaged in the tasks of scientific inquiry from the development of the question to the answering of the question.  Meanwhile, I am able to observe their work and make judgements about what students can and cannot do as a result of their participation in my course.

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 learning more about his Scientific Investigations website to visit his course pages at http://gbschemphys.com/chemphys/lab/project/project.html.

Other Gab: Why Do Demos?

Last year was the first year in 10 years that my teaching assignment involved teaching Chemistry. As a cross-over to Chemistry, there was much to re-learn, much to develop, much to get accustomed to.  As they say "You can't do it all" and I most certainly didn't. What was most lacking in my teaching of chemistry was a repertoire of effective demonstrations. When I received the same assignment of teaching two sections of chemistry during this school year, I made a pledge to myself to do a demonstration each day (at least each day in which there wasn't a lab experience). My thought was that my students should be doing chemistry and seeing chemistry on a daily basis.  Every day should include chemistry; not just talk about chemistry or calculations about chemistry, but actual chemistry. Chemical reactions should happen. Chemical properties should come alive.  After all, it's a science class and science should be happening.


There's no doubt about it!  Students love chemistry demonstrations.  And physics demonstrations. And any science demonstration.  And I love them too!  Who couldn't love a science demonstration?  Science museums stay in business not because there are a bunch of people inside showing PowerPoint slides; and not because there is an opportunity to sit around tables solving stoichiometry or projectile problems; and not because there are booths where you can sit down and balance chemical equations or draw free-body diagrams.  Rather, science museums stay in business because there are interesting things to look at, to watch, and to interact with. And when these things happen, people learn.  And the learning that does happen is more closely tied to the content which is being learned; it is not abstracted, detached, nor remote.


Students love demonstrations.  They enjoy them.  But do they learn from them? Now that's a tough question.  And an important one.  After all, my science class should be about more than just having fun.  It should be more than entertainment.  If my professional goals centered around providing fun and entertainment for others, then I should have sought to obtain a job at a museum.  Or at a zoo. Or in a circus. But my professional aspirations are centered around educating high schoolers and that naturally landed me a job in a high school teaching science.


In addition to a couple of lab experiences, there were three noteworthy demonstrations this week in my chemistry class. On Monday, we were talking about solubility and saturation of solutions.  To demonstrate a supersaturated solution, a hunk (new measurement unit) of sodium acetate was placed in a beaker of 10 mL of water.  It was heated and heated and eventually dissolved; there's a definite chemistry lesson in this.  Then the solution of dissolved NaAc (as it is affectionately known) is poured into a clean buret;  it cools over the next 30 minutes as we discuss variables effecting solubility, solubility curves, unsaturated vs. saturated vs. supersaturated solutions, etc. Near the end of class we return to the back of the room. The solution drips from the buret onto a watch glass with a single crystal of NaAc.  Students watch in amazement as the dissolved NaAc immediately crystallizes, forming a tall column of undissolved solid.  (View picture.) Entertaining? Defintely!  Enjoyable? Clearly. Educational? Potentially.  For certain, the entire cycle of dissolving the NaAc at high temperatures, allowing for supersaturation through cooling, and ultimately the crystallization of the NaAc as it dripped from the buret was the bridge which connected the content of the lesson to the real world of chemistry.  Thanks to the demo, the content was no longer abstracted, detached nor remote;  rather, it was alive and happening before their very eyes.  Big bang. Big buck.


As a St. Patrick's Day demonstration this past Wednesday, some boric acid was dissolved in methanol, squirted on a lab table in the shape of a shamrock and lit.  For 20-30 seconds, a green flame in the shape of a shamrock emerges from the lab table. The green of the flame is a characteristic of boron's emission spectra.  Students responded immediately: "Cool" "Wow!"  "OMG" "Do it again!" After three more repetitions and about three more minutes, students were back in their seats cranking out molarity calculations. Little bang, little buck. This is a demo that's mostly entertainment. Definitely fun. (And unfortunately it did leave with a lot of leftover boric acid and methanol.)


On a third day this week in chemistry class, I complemented a lesson on molarity and dilution with a demonstration in which two solutions were made by dissolving a known amount of copper chloride in a 200 mL volumetric flask of water.  Lab techniques were demonstrated and students calculated the concentrations.  One solution was five times the concentration of the other. We noted the color of the two solutions; that was a separate lesson in itself.  Then I took out 40 mL of the more concentrated solution and placed it in a third 200 mL volumetric flask;  we calculated the moles of copper chloride present in that 40 mL.  Then I added water to this 40 mL to fill the flask to the 200 mL mark.  As I added the water, I asked students how much copper chloride was I presently adding;  they all agreed - none.  When finished diluting the solution, I asked students to calculate the concentration.  We all agreed that the new concentration was the same as the concentration of the more dilute solution; we noted the color.  I discussed the concept of dilution, dilution calculations and a dilution factor.  I thought this was big bang.  Attachment of content to real world. The dilution concept from the textbook coming alive. A chance to discuss good lab technique. A chance to demonstrate the types of questions which a chemist asks. A chance to see chemistry happen. Entertaining? Not really.  Enjoyable? I enjoyed it; my students would rather be watching green flames or see a column of NaAc grow tall. Educational?  Potentially.


Why do demos? is the question I am pondering.  Why skip demos? is a question which is easy to answer.  They take time to prepare. (Planning, practicing and preparing the dilution demo took me close to 50 minutes. Preparing and practicing the NaAc demo took me a half hour.) They take time to clean up and sometimes they are a pain to clean up. (The boric acid is mildly toxic; methanol causes blindness if ingested; and my St. Patricks day demo left me with an extra 200 mL of toxic mess to dispose of.) They cost money (equipment, materials, chemicals). They take class time to perform.  Sometimes they don't work as intended and I get embarrassed (but a good humbling isn't always a bad thing). Sometimes its difficult to think of a demo appropriate to the current topic. (The combustion of the methanol with the boric acid doesn't exactly have a solution theme.) And sometimes we believe that the class time spent showing students demonstrations could be put to better use by doing more educational activities, which usually means doing more drill and practice type work. (For certain, in the time it took me to mix two solutions and then dilute one to the concentration of the other, I could have done at least twice as many molarity and dilution problems.)  So if Why skip demos? is a question which quickly evokes some valid answers (or at least some appealing answers), then Why do demos?


As I was cleaning up my mess after class on Thursday, my demo a day commitment came under personal scrutiny. Was there any value to what I was doing?  Was I getting any bang for my buck?  Why was I exhausting myself with demos?  I walked back to the office pondering these questions. When I arrived in my office I observed Mrs. S at her desk.  Mrs. S is a veteran in the trade of doing demonstrations. Mrs. S is a chemistry teacher in our department who has a reputation among her colleagues and her students for loving demonstrations. Mrs. S is definitely a demo a day teacher. And to her credit, she does her demonstrations with flare (no pun intended).  As there should be, there is a sense of entertainment, even theatre, when Mrs. S does chemical demonstrations.  This is not to say that there is no learning going on;  it is simply to say that the learning occurs in an environment which captivates her lower-level chemistry students. Her students are hooked!  What teacher wouldn't want that?


Hoping for some encouragement, I posed the Why do demos? question to Mrs. S. Without hesitation, she gave me what seemed to be 30 answers to the question. Here is her take on the question:

• Demonstrations provide a sort of "visual cement" for a science course; they provide visual reinforcement of the content material.
• Students will most likely remember the material which is demonstrated. When they reminense about your class, they won't be thinking about worksheets, tests, or PowerPoint slides; they will be remembering your demonstrations.
• Demonstrations bring the textbook material to life and provide relevant application of the content.
• Demonstrations address the need to appeal to the varying learning modalites of students.  For many students, seeing is believing and seeing is learning.
• Demonstrations provide a avenue for critical thinking as they often naturally lead to the question why does this happen?
• Demonstrations pique student curiosity; students become more invested when their curiosity is piqued.
• Demonstrations provide an interesting diversion amidst an otherwise drab lesson plan, providing students with an interesting chunk to chew.
• Committing oneself to doing demonstrations encourages a teacher to grow professionally as they learn new ways to present and reinforce content material.
• Demonstrations are FUN - for both teachers and students.  They create an atmosphere of exciting inquiry within the classroom.

Shortly after having finished her list, Mrs. S began to bolt out of the office towards the prep room to prepare her upcoming rendition of a chemical demonstration.  Out of the corner of my eye, I observed her tie-dye lab coat flash by me.  I stopped her and asked if she would be interested in my left-over methanol-boric acid solution.  As a veteran of the trade, she knew exactly what it was for. She gladly accepted my offer. And I was quite relieved to have pawned it off on her.  Whew! What a relief.


The rest of my lunch period and prep period was busy as I prepared for my afternoon physics sections.  I had little time to continue my ponderings until 5 minutes into my first afternoon physics class;  the fire alarms sounded and the whole school was evacuated.  This gave me a few more minutes of further ponderings on the topic of why do demos? As is usually the case, the fire alarm was a false call and we returned to our classed to finish the school day.  


On my 30-minute trek home from school, my car ride thoughts returned to why do demos? I began to think about all those former students, who when reminsicsing about their experience in my course, would inevitably make a comment pertaining to demonstrations.  I've never heard such a student make comments like "I remember that one PowerPoint presentation on inertia" or "Have you designed anymore cool worksheets for your students to do" or "Do you still use that one Powerpoint presentation on ..."  No! Never!  This is not what my former students remember. The record is clear; they make comments like "I still remember that one demonstration when you made the aluminum rod make a sound by stroking it with your hand" or "Have you come up with any new demonstrations to show your students" or "Do you still do that demonstration when you shoot the falling monkey with your projectile launcher?" Students remember my demonstrations and your demonstrations for a reason. Demonstrations are meaningful; they stick in their heads.  Demonstrations are visual; they can't forget them.  Demonstrations are engaging; they hook kids attention. Demonstrations provide the connection between the concepts we are talking about and the material world which those concepts seek to describe.


Demonstrations are probably the closest thing in our profession to edutainment. They are an engaging and (at times) entertaining means of educating our students.  And they are an educational means of entertaining our students.  When a professional teacher transparently embeds a demonstration with the lesson content, students become engaged in the lesson.  Student investment in the lesson rises and And when the demonstration is presented using effective pedagogical strategies, higher rates of learning inevitably results.  A lesson immersed with showing students the operations of the material world is a lesson students will remember. Now what teacher wouldn't want that?


I got an email from Mrs. S the next morning: "By the way, one more reason to do demonstrations: total school evacuation." Now I am really glad I pawned the methanol-boric acid solution off on Mrs. S.  Better her than me.