Tag Archives: labs

Nuclear Physics Project

This year, after completing our four major units of second semester in regular physics, we planned on a project that would address Illinois Science Goal 13: “Understand the relationships among science, technology and society in historical and contemporary contexts.” This project has the potential to move beyond content and integrate perspectives from many other disciplines. I had some ideas in mind, but after the Fukushima disaster, my colleague and I decided that our final project would focus on nuclear physics. Here is the description of the project that we will distribute to students:

Download (PDF, 51KB)

One aspect of this project that I’m really excited about is that we will be publishing all of the projects on Wikispaces so that they can be viewed by other students and professional both within and outside of our school.

I’m also very excited about the manner in which students will present their projects online. In order to highlight how technology influences the communication of scientific ideas and events throughout our society and how that has changed throughout history, we’ve encouraged students to create a juxtaposition between the time period of the topic and the presentation method that they select. For example, if their topic is historical, choose a presentation method that is modern (e.g., Marie Curie and her Facebook status updates). Or, if their topic is modern, choose a presentation method that is historical (e.g., black-and-white news documentary of fusion reactor).

I’m very interested in your feedback or involvement. Do you know of other topics related to nuclear physics that we should add to our potential topics list? Do you have ideas for other engaging presentation methods? Are you or your students interested in viewing and commenting on these projects in late May? If so, please contact me either via Twitter (@gcschmit) or via e-mail (geoff at this domain). Regardless, when the projects are published, I’ll post the link here.

**Update: 20/6/11 11:09 PM**

All of the student projects are on [nnhsphysics](http://nnhsphysics.wikispaces.com/) wiki hosted by [Wikispaces](http://wikispaces.com/). I created an [index of sample projects](http://nnhsphysics.wikispaces.com/Sample+Projects) which contains projects on a variety of topics created in a variety of mediums.

Circuits Lab Practicum

This year, we created a new lab practicum for the circuits unit. In addition to the traditional activities of having students draw a circuit diagram from a written description, build the circuit, and measure the voltage across and current through a specified resistor; students had to infer the circuit diagram for a collection of lightbulbs based on their observations.

This activity was inspired by an old Science Olympiad circuits event. As shown in the following photo (which is somewhat hard to discern due to the pattern of the fabric), four labeled light bulbs protrude through holes in the fabric. The fabric hides the wires connecting these light bulbs. Students turn on the power and then make observations by unscrewing and screwing in the light bulbs. Based on their observations, they draw the circuit diagram and justify their conclusion.

circuit lab practicum

Students were most engaged in this activity of the lab practicum compared to the others. I think the fact that it was a unique way for them to apply their knowledge and inference abilities made it so interesting. It also had the unexpected benefit of reinforcing the idea that physical order of the light bulbs has no effect on their brightness. That is, the first light bulb in series from the positive terminal of a battery is not the brightest because it is “first.” Several students commented that there were several circuit diagrams that they could draw that would match their observations. It was reassuring that they came to this conclusion!

Measurement Uncertainty Activity

In previous years, my students have always struggled to really understand measurement uncertainty. Due to my background in the computer-based measurement and automation industry, I was always troubled that I didn’t do I better job helping them understand. So, this year, I developed a set of six activities to provide a hands-on way to practice applying the definitions as well as provide a context to discuss the complexities of measurement uncertainty. Each group investigated one of the activities and then whiteboarded and presented their results with the rest of the class. Each activity had the group determine the measurement uncertainty of a measuring device and calculate the maximum percent uncertainty of their measurements. However, each activity also had a deeper purpose that led to good class discussions during whiteboarding.

1. Measure the dimensions of a block with a ruler. Deeper purpose: calculate the percent uncertainty of the volume of the block.

2. Measure the width and length of the lab table with a modified meter stick (cm precision). Deeper purpose: how does having to make multiple measurements to measure the length affect the measurement uncertainty?

3. Measure the period of a pendulum with the wall clock. Deeper purpose: how does the percent uncertainty change if 2, 5, 10, or 20 oscillations of the pendulum are measured instead?

4. Measure the temperature of ice water and hot water with a digital temperature probe. Deeper purpose: is the percent uncertainty of the cold-water measurement actually greater than that of the hot-water measurement? How does measuring the temperature differ than all the other measurements (difference vs. absolute)?

5. Measure the time for a ball to drop from the table to floor and the ceiling to floor with a digital stopwatch. Deeper purpose: Are the measurement as precise as the measurement uncertainty of the digital stopwatch (1/100 of a second)?

6. Measure the speed of the cart on the track using a photogate connected to the computer. Deeper purpose: What does the computer actually measure? What determines the measurement uncertainty? Determining the actual uncertainty of a photogate connected to a laptop running Logger Pro via a LabPro is well beyond the scope of this course (although, in my Advanced Physics course, we figure it out). Still, students realizing that computer-based measurements don’t have infinite precision is an important lesson.

The class discussions that occurred while whiteboarding were fantastic and this year’s students have a much greater appreciation of measurement uncertainty than those of previous years.

Polar Bears around an Ice Hole

I started some of my classes today with the “Polar Bears around an Ice Hole” riddle:

> The game is in the name of the game – polar bears around an ice hole – invented in the days of Ghengis Khan.
>
> A clue for you to keep you true – like petals around a rose, you can count each bear’s nose.
>
> How many polar bears do you see?

You then roll a bunch of dice. (I created six 5″ dice from styrofoam and black pom poms.) A physics teacher from another school uses this as his introduction activity on the first day of school and shared the activity a couple of years ago. I had planned on using this activity as an extended analogy to introduce specific aspects of the class culture:

* You may feel frustrated as you try to figure physics out. That’s okay.
* Physics is hard to understand until you know the “rules of the game.”
* But, once you discover the rules, physics often seems easy and you may be surprised that others don’t understand.
* However, remember that you didn’t always understand.
* When you discover the rules and understand without someone just telling you the “answer”, you are excited.
* The journey to understanding is very important. So, no one is going to tell you the answer, but we’re all here to support each other on our journeys.
* Being told the “answer” at most gives you one answer that you didn’t know. Learning to think critically and arrive at the answer with support develops a skill that you will use to find many answers.

As the activity progressed, I realized that this activity also served as an excellent example of scientific inquiry. As we continued to try and solve the riddle, I introduced several important ideas:

* make careful observations
* gather lots of data (many roles of the dice)
* look for patterns, compare and contrast, look for extremes
* simply the problem being investigated (roll fewer dice)
* constrain the variables (set dice to specific values)
* propose a hypothesis, test it, modify it based on results, repeat

After discussing the activity, I grabbed my notebook and nonchalantly asked who solved the riddle within the first five minutes. I then announced that they would receive As for today. I then asked who solved the riddle in ten minutes and announced that they would receive Bs. Next, who solved the riddle in fifteen minutes and announced that they would receive Cs. Everyone else would receive Fs. This provided a great hook to transition to our discussion about standards-based grading.

I Like Reading Lab Reports

When I first started teaching, I loathed grading lab reports. I had a seemingly never-ending pile of papers almost a foot tall sitting on the front, right-hand corner of my desk glaring at me with that look of “we’re not going anywhere, you know.”

Eventually, I would grab a chunk of labs and my green pen and start reading. I would read each lab and deduct points for errors and omissions. Sure, I would write comments and feedback as well, but I found it challenging to have both a point-deduction-centric perspective and feedback-centric perspective in my head at the same time. Even with a rubric, I spent a lot of time debating with myself, “Is this vague statement *close enough* to receive full credit?” “This paragraph shows some understanding, but I can’t tell what this student really understands; -1 or -2?” After grading a lab, I would flip back through each page counting how many points I had deducted. Not being a very number-centric person, I would at times ask myself, “Wait, is this lab out of 20 or 25 points; let me check.” I would then check to see if I had made a note on the lab that it was submitted late in which case I would apply a late penalty as well which wasn’t always simple: “Okay the 20th was four days ago but I think we didn’t have class one day; let me check…. Ah, we didn’t; so, that only counts as three days late.” At times, I would question if a specific error or omission should result in a one or two point deduction and, under the guise of fairness, I would search through previously graded labs to find one that I vaguely remembered having made the same error or omission. I spent hours and hours grading lab reports.

When I finished grading a lab for the entire class, I would hand it back but worry that, once I did so, students who hadn’t turned in the lab would copy a friend’s graded lab and submit it as their own. When I did hand back the labs, I would watch students’ reactions. If I put a grade on the front of the lab, they would look at the grade and apply, perhaps subconsciously, an algorithm that resulted in a positive, ambivalent, or negative feeling and then file the lab in their folder. *Many wouldn’t even flip through the pages to read my comments.* After noticing this pattern, I started writing the grade on the last page. Many students would then skim their graded labs, but they weren’t reading my feedback; they were scanning for the grade that they knew must be in there somewhere. If I forgot to total the points and write the grade on a couple of labs, they would certainly ask about their grades. However, the students were so entrenched in the grades game that I never had any ask for feedback if I didn’t write comments.

**This sucked. Grading labs was my least favorite part of teaching. There had to be a better way.**

Last year, myself and a colleague integrated our fledgling standards-based grading philosophy into our honors physics classes. We categorized most of labs that were previously graded as learning activities which we defined as “activities that don’t directly affect your grade, they are essential in that they are your opportunity to explore, discover, take risks, make mistakes, ask questions, help each other, practice, and get feedback before having to demonstrate mastery.” We explained this to our students and started our first lab activity. The next day, everyone turned in their labs.

I went home that night and I didn’t grade their labs. I *read* them. As I read them, I wrote comments, asked questions, made minor corrections. I never thought about points. I didn’t calculate a score. It was wonderful.

The next day in class, I handed back the labs. This new standards-based grading methodology was unfamiliar to the students and many hadn’t internalized the role of these learning activities. I observed some students scanning their labs for a grade. “Mr. Schmit, what is my grade on this?” “It is a learning activity, no grade; just feedback.” As they began to understand that no matter how hard they looked, they wouldn’t find a 18/20 anywhere in their lab, I saw students actually reading my feedback. Some students even asked questions about what I had written.

Lab reports got better. As students embraced the standards-based grading philosophy, they started taking risks because they weren’t worried about losing points. The vagueness of statements was diminished. Students began to write what they actually thought instead of what they thought was sufficiently generic to result in credit. Some students even started writing questions in their lab reports to ask for clarification. Many times, after a productive class discussion or whiteboarding session, I wouldn’t feel that I needed to collect the lab reports and provide additional feedback. The students had already provided all of it to each other.

I had a number of goals, hopes, and dreams when I started standards-based grading last year. Liberating students from grading such that they could focus on their learning was one. Liberating myself from grading such that I actually enjoyed reading lab reports wasn’t one of them, but it was a very pleasant surprise.