A Unit on Units, Two Ways

I always think it’s interesting to see how similar classes at different levels and grades learn the same topics.  This year I’m teaching both freshmen physics and regular level upperclassmen physics.  In both classes we began the year with a unit on units, measurements, and conversions.  Each class learned the basic concepts but had the opportunity to apply the concepts in two very different ways.

Freshmen Physics – Make Your Own Unit

All freshmen at Pomfret School take the same level introductory physics course.  This is great because they all share in a common experience, even if they have a different teacher.  Fellow teacher, Josh Lake, and I work closely to create each unit and keep our classes paced together.  This year, students worked on a lab where they were tasked to create their own unit.


A student measuring his tie using his unit, a AA battery.

Students embark on a several day lab where they measure common objects in the classroom, find conversion factors, and standardize their unit to the metric system.  In years past the lab ended there, but this year, Josh and I decided to have the students create an art installation with their own units.  It turned out really well, students transformed a drab white walled stairwell into a pretty cool hanging art display.


Upperclass Physics – Scaling Our Solar System

In the upperclassmen physics class I decided to up the difficulty a bit and provide the students with a bit of an open ended project based experience.  The goal of the project was to create an installation along a long hallway leading to our classroom.


Our hallway just before installation.

On the first day of class I presented the students with a properly scaled model of the Earth and the Moon and then had each of them select a random sphere from a box.  They then used that sphere as a starting point for their own individual model.  Students chose a celestial body in our solar system to represent their sphere and then picked a second body to create their model.  They had to determine their scale and then use that scale to determine the proper size of their other object and the


Each class makes peer feedback norms.

distance between the two.  Along with the physical model, they create a one page description of the model and we go through two rough drafts and peer editing before they are ready to hang everything on the wall.  In the end there were more than 40 objects on the wall, connected by pink string, each with a description mounted on foam core.  One student said after hanging her model, “At first I wasn’t sure what you had in mind, but now I love it!”




The final product of their work on display.

Putting Student Work on Display

Although I loved my physics major in college I got just as much joy and sense of accomplishment from my art minor.  I was constantly creating things and putting them on display for critique and public viewing.  It made me take a little more pride in my work when I knew it was going to be hung with my name near it.  For many of our students this was the first time they had to create an art style display for their scientific work and many of them struggled to move forward with it.


Students painting their spheres before hanging them on the wall.

Now, especially with the upperclass project, when the students walk by they always check on their display, making sure it’s still hanging straight and looking good.


A completed model.

There’s never much physics content learned in the process of putting their work on display but I have felt that the extra pride they take in their work translates into a better final product and more learning along the way.


Students working on their units display.

They ask more questions about things they are unsure of because hanging something out on display with an error for all their friends to see is sometimes more scary then getting a bad grade.  In my eyes, taking the time to put student work on display is time well spent.





Students working on their display.  Fellow teacher, Josh Lake, in the background.


From Slide Rules to Mathematica

It’s hard to believe that we use to carry out complicated computations on something that required no batteries to operate, had no screen, and no buttons; it was called a slide rule.  I have no idea how it even worked, just take a look at the photo below…


These things were complicated, yet they powered the analysis of complex mathematical systems and provided a quick way to perform calculations.  According to the website, The Museum of HP Calculators, the slide rule reigned supreme for about 300 years.  You can even take a look at the instructions for its operation here, it’s not very intuitive at first glance.

We’re almost 400 years post slide rule invention, credited to William Oughtred in 1622, and technology has brought us a long way.  At Pomfret School we provide all students with a Wolfram account and the science department requires all students to download, install, and use Mathematica to perform a whole host of operations.  Students are first introduced to the program in our freshmen physics class where we work to provide them with all of the skills and know how to use Mathematica (MMA) confidently.


We begin the year with a simple lab where students use Mathematica to calculate percent error, a value that we end up using frequently


Student write-up submitted for grading.

throughout the year to inform students of their own lab/data collection skills.  The lab centers on the Vitruvian Man and the students
use the ideal proportions and their own measurements to calculate percent error.  They then write-up the lab in Mathematica and submit it for grading.  This is definitely not second nature for most of our students and many struggle with the programming nature of the input and formatting nuances of the program.

With some practice and after many failed outputs, about 90% of the students are ready to move on, and to begin tackling harder material on their path to unlock the power of such a robust program.  We move into units, measurements, and conversions next and present the students with a lab where they make their own unit and learn how to convert measurements using Mathematica.


All lab handouts are made using Mathematica so students are interacting with the software on many different levels.

At this point we are just two weeks into class, and we begin to show students


Notes can be easily formatted and images inserted in MMA.

how Mathematica can be used to take notes as well.  It’s interesting to note that although we have spent time teaching the students how to use Mathematica we have also been able to move through typical freshmen year content at a reasonable pace.  This lab, unlike the last, incorporates the use of more complex mathematical skills and reasoning.  Mathematica allows students to see the format of the conversions, much like on paper, but are less intimidated by the process of solving the equation.  As the students begin to see the merit in


Student generated conversion practice.

learning the Mathematica input language we begin to see them embracing the fact that they don’t have to worry about inputing their work on paper into their calculator.  What was once a two step process on paper and with a calculator has now become one step in Mathematica.


We’re almost three weeks into the school year now and I’m 100% behind the use Mathematica in the classroom.  It has allowed students to solve mathematical problems, take notes in class, and learn how to do some basic programming.  It makes me wonder what it would be like trying to teach these students how to use a slide rule…

I have to also give a huge amount of credit to my fellow teacher, Josh Lake, as much of this content was generated initially by him.


New School & New Beginnings

This year I start my tenth year teaching and working at independent boarding schools.  Last year my wife and I decided to move our family of 5 out of the city and into an environment better suited for our three little ones.  We’re excited to be working and living now at Pomfret School, in Pomfret, Connecticut.

We’re just a week into classes now and I’ve been exposed to a whole host of new technology tools that I have never used before.  I’ll try to highlight them here:

  1. Google Classroom: At Pomfret students are setup with a Google e-mail and all of the Google apps suited for education.  Google Classroom seemed to be the perfect choice as an LMS for myself and the students this year.  It has taken some time to get use to but we’re both starting to get the hang of it.  The more I use it the more I like it.screen-shot-2016-09-15-at-1-31-09-pm
  2. EDpuzzle: This site is amazing.  What a great way to assign formative assessments and to keep students engaged outside of the classroom.  I’m not a huge proponent of a 100% flipped classroom but this has made it quite easy to bring more meaning to homework.  We just upgraded our school account and it allows for unlimited access and sharing of videos within the school and access to their new gradebook, well worth it.Screen Shot 2016-09-15 at 1.32.56 PM.png
  3. Mathematica: All of the students at Pomfret are given a full license to Mathematica and we use it extensively in the Science Department.  It takes the pain of the math out of the learning of science.  There is a bit of an adjustment to the programming style of the software but students and myself alike are getting the hang of it pretty quickly.Screen Shot 2016-09-15 at 1.35.09 PM.png

Hoping I can keep the blog updated this year and share more stories and ideas from the classroom.

Deadly Gorge Bungee Design (Energy Practical)

After seeing many videos and images of other high school physics classes doing some variation of a bungee jump, we, fellow teacher Jeremy Smith and I, decided to implement one of our own.  This turned out to be a great way to wrap up our energy unit as students would be exposed to all three types of mechanical energy in this problem.  Our Deadly Gorge Bungee Jump Design was simple, it asked students to design a bungee jump that could work for a range of customers, in this case masses ranging from 100 g to 750 g.  Materials were limited to springs(we’re fortunate enough to have several sets of these that work great), string, and an adjustable ring stand.

IMG_1632It was really interesting to watch as the students got started right away.  Almost all of the groups began by simply playing with the materials, I often encourage this with new materials in class, just so students can learn on their own how they work.  Quickly following this initial play period was the adjust and check period.  There were no calculations being done, simply students writing down the height of the jump point and whether it hit the ground or didn’t come close enough.  I try not to step in too much with these types of problems, hoping that students will eventually apply the equations to the problem.  At the start of the next class period I helped the students talk through a conceptual understanding of the setup, including the variables and energy types.  This helped tremendously as groups started to work through the problem on paper.  About half of them had it, the other half just couldn’t get past the number of variables.  Those groups that struggled ended up coming to see me for some extra help and we talked through it together.


On test day students chose one of 5 random masses and setup their jumps according to their calculations and testing.  Not all groups were successful on test day, with some groups dipping into the water, one group hitting the bottom, and a few just missing.  It was great to see their reactions and the groups that didn’t get it went immediately to figuring out why it didn’t work.



This setup allowed groups to adjust one of three variables in order to be successful.  They could use a different spring, a different length of string, or adjust the height of the ring stand.  All three of these methods were employed in my class, the easiest adjustment though is simply to change the height of the ring stand according to calculations, this ends up being a quadratic with two solutions, one being negative.

One aspect of the problem that I’d like to quantify is the acceleration of the mass as it is slowed, as an actual bungee jump needs to do this smoothly so the customer doesn’t experience whiplash.


Scratch Programming and Kinematics

Like many high school physics students our honors students start the year by learning kinematics.  Over the past two years we have integrated programming into the unit with the use of Scratch.  We still do many hands-on demos and labs but have found that adding this aspect to the unit gives the students a chance to apply their learning and receive immediate feedback on their understanding and application.  Scratch is a very user-friendly block based programming language and students are able to build their skills while not feeling overwhelmed with lines of code.  By the end of the unit we have completed one and two dimensional motion and students really are able to grasp the equations of motion.

Before we start with the actual physics we introduce some basic concepts of programming and how Scratch is structured.  This takes about 30 minutes of class, a very broad overview.  After this we ask the students to create something, anything, on Scratch.  This results in some interesting, simple, and complex first programs.

The unit begins with a simple problem: 1D Motion Scratch Lab which is graded using this rubric 1D Motion Scratch Lab Rubric.  This problem asks the students to create a program where the user can input initial position, initial velocity, and constant acceleration.  These inputs need to control the motion of the sprite on the screen. Some student examples: Student 1, Student 2, Student 3.

Screen Shot 2015-03-26 at 9.50.18 PM

From this first project we build on their programming skills and understanding of kinematics phenomena through the following projects:

Independent Variables Simulation: Create a Scratch program that mimics a simple in class demo of a ball rolled off a flat table and one dropped from the edge at the same time.  Some student examples: Student 1, Student 2, Student 3.  I grade this project using this rubric 2D Motion Scratch Lab Rubric – Ind Var.  This rubric was partially created by the students picking the categories they believed they should be graded on.

Screen Shot 2015-03-26 at 10.15.45 PM

Animate a 2D Problem: Students create a unique 2D problem that can be solved by user input.  The program runs according to user input and shows if the solution is correct or not.  This is the student handout 2D Scratch problem and students graded each others programs using this grading sheet 2D Scratch problem Student Grading.  I ended up grading the programs using the same sheet after they made changes from student feedback.  Some student examples: Student 1, Student 2, Student 3.

Screen Shot 2015-03-26 at 9.51.54 PM

Runner/Jumper Animation: Students animate a sprite that runs and jumps according to the 2D motion that was described in class, specifically constant horizontal velocity and accelerated vertical velocity.  This program really requires a lot of problem solving as user controls need to be ignored while the sprite is in the air.  Here is the student handout Runner-Jumper Scratch Problem and graded using this simple sheet Runner-Jumper Scratch Problem Grading.  Some student examples: Student 1, Student 2, Student 3.

Screen Shot 2015-03-26 at 9.52.37 PM

Runner/Jumper Video Analysis: This is the final piece to this unit and essentially replaces our old kinematics test.  Students take a video capture of another student’s runner/jumper animation and analyze the motion of the sprite using Logger Pro video analysis.  Here is the student handout Kinematics Analysis and graded using this simple sheet Kinematics Analysis Grading.

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I have to give a lot of credit to my fellow teacher, Mr. Smith, for his ideas and collaboration on this unit and its content.

Cart Races Lab Practical

I borrowed this idea that I originally saw from @rutherfordcasey and @kellyoshea.  I am always thinking about ways for students to collect data and to be able to assess their methods using that data.  So I decided to time the finish using two force plates, allowing us to quantify the race.  This turned out to be a rewarding lab practical midway through our Newton’s 2nd Law unit.


The students received a fairly simple set of questions to guide them through the process and to give me something substantial enough to assess their understanding.

Newton’s 2nd Law

  1. Using the setup at the front of the room calculate where the two carts must start from in order to hit the force plate at the bottom of the ramps at the same time. The carts must travel a minimum of 1.0 m. Show all of your work in a neat and well organized manner below. You must provide some narrative to describe what you are solving for in each step.
  2. Test your calculations. How far off are you, is it within an acceptable amount of error?
  3. If the two carts do not hit at the same time, within an acceptable amount of error, re-evaluate your solution and perform the test again.
  4. What sources of error exist in this experiment so that your theoretical values do not match what actually happens?

In small groups the students worked through the solution and began testing.  They also learned how to measure the angle of an incline using a protractor and plumb bob.


The 1.0 m minimum forced them to put more thought into the kinematics of the carts’ motion which was a great review of prior material.  After calculating and running their tests all groups were able to get great data, with the carts hitting within 0.10 s of each other.

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Opening My Classroom Door

Since beginning my teaching career in the fall of 2007 I have always invited colleagues to visit my classroom, telling them that my door is always open.  I’m hoping that this blog will allow me to open my classroom door to a larger audience to encourage feedback and comments on the teaching and learning that happens within.

My name is Derek Segesdy, I have been teaching physics at the high school level for 7 years, now in my 8th.  I currently teach at Worcester Academy, an independent day and boarding school in Worcester Massachusetts.  I am also the Science Department Chair and work with department members teaching science from grade 6 through senior year.  At Worcester Academy we teach physics as a third year course, preceded by biology (freshman) and chemistry (sophomore).  I have also taught physics first at the Fountain Valley School in Colorado Springs.

Recently I have been inspired by the blog posts of @rutherfordcasey, @fnoschese, and @reilly1041.  I will try to follow suit by sharing some of what we do in our classrooms as well as some general thoughts about teaching and learning at the high school level.