Beats by ______ | Project Based Learning

One of my favorite labs to emphasize testing and controlling variables is the classic pendulum experiment. Typically this is framed in a procedure prompting students to perform trials where they change one variable about the pendulum set up and collect data about how the frequency of the swing is affected. This is repeated for the mass of the bob, the string length, and the pull back amplitude. It's a surprising conclusion for many that only the length of the string affects the frequency but the numbers don't lie. 

This year, in my quest to projectify my class, I redesigned this lab around a single task: Design and build a swinging light prototype that can be modified to match any tempo. Of course, there is a whole backstory of the students acting as a design firm prototyping some swinging stage lights for a famous pop group, but that is just there to provide some context and motivation to the task.  

With this task, it's all up to the students  to design an experiment to test the different variables, collect data, and model the system. The requirements document to the right includes an engineering design process that helps groups frame their thinking. The framework included some suggested checkpoints but the procedure was all on them. 

Beats by _______ - Requirements.pdf
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Beats by ___ - Requirements - Google Doc

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I didn't give any procedures for today's pendulum project. It took more time, but the learning felt different. Deeper. #PBLchat #Teach180

— Joe Cossette (@cossettej) September 30, 2015

The work time that I gave them in class was really fun to watch. Many groups ended up developing a very similar procedure to the one that we used to give them. The difference was that this was their procedure, not mine. They were experimenting because they decided that experimenting was important.
There is no question that the process took longer with this approach but for the depth of learning that I witnessed in this process, I'm willing to make that sacrifice.​​

Overall, we probably spent close to 4-5 partial days working on the prototypes before they were asked to demonstrate their effectiveness and accomplishing the task. In this time, they needed to figure out away to collect enough data to model their system (either graphically or mathematically) so that they would have something to guide their design during the demonstration.

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The Challenge

On Demonstration Day, students were given 15 minutes to set up their pendulum prototypes and complete any last minute tests.

Round 1:
After the 15 minutes, each group had to demonstrate that their pendulum could accurately swing to the beat of the song of their choice. 

Round 2:
After all groups demonstrated their first song, I played about 30 seconds of a challenge song that had a different tempo than any of self-selected songs. (see the list of challenge songs on the right) I didn't tell them the BPM of this song so groups needed to use an online metronome to tap out a custom tempo. Each group was given exactly 5 minutes from this point to use their data to set up their pendulums. There was absolutely no testing allowed during this time period. This eliminated the possibility of trial and error. They HAD to use the data that they calculated.

#Day21: can you create a mathematical model to make your pendulum swing to the beat of any song? #PBLchat #Teach180 pic.twitter.com/vlq3o9AHC6

— Joe Cossette (@cossettej) October 6, 2015

Challenge Songs

80 BPM  -  Heaven  -  O.A.R.
86 BPM  -  Bye, Bye, Bye  -  N*SYNC
95 BPM  -  Good Life  -  One Republic
99 BPM  -  I Want it That Way  -  Backstreet Boys
125 BPM - September  -  Earth, Wind, and Fire

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Rubric

To give students a little guidance and structure in their reports, I provided them with a detailed 18-item rubric outlining my expectation. For each line item, I awarded students a 3, 2, or 1 based on how well they embodied the provided description.

As an extension during this unit, we did a mini lesson about using Microsoft Excel to linearize data and derive an equation to model the pendulum system. Typically, a pendulum system is modeled as a relationship between period and length but in this application, period is a less useful figure to calculate for. Instead, many groups graphed BPM vs length. This relationship is an inverse root curve so they needed to figure out to raise the length value to the -0.5 power, a huge challenge.

To factor in this extension, the rubric was intentionally designed to be out of a possible 54 points (even though it was graded out of 50). This acknowledges the challenge of the linearization and allows students to score above 100% if they take on the challenge.

Beats by _______ - Rubric.pdf
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Beats by ______ - Rubric - Google Doc

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Example Reports

Example Report 1.pdf
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Example Report 2.pdf
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Example Report 3.pdf
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Reflection

Overall I was very happy with the results of this project. I felt that it truly challenged the thinking of many of my students and it led to some really interesting conversations about the hows and whys of setting up experiments within different groups.

I also asked for feedback from students about what they thought about the project itself. The results were split many students liked the challenge and open-endedness of the project but that also caused a great deal of anxiety for some. There is also a disconnect where students still don't see projects as a way of learning. I hope to be more explicit with the learning targets that I hope to hit in the next project.

"Not having a lot of instruction built my independence and confidence."

"I liked it at first it seemed hard but then became really interesting as I figured it out"

"Really challenging, but it really made us think"

"It was unnecessary and time consuming. We could learn the same amount of material in less time for each unit without a project."

"I was frustrated that you didn't tell us which variable to test. it made the whole process much less concrete which makes it harder for me to learn well"

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Files

Beats by ______ | Requirements | Google Doc

Beats by ______ - Requirements.pdf
File Size:	202 kb
File Type:	pdf

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Beats by ______ | Rubric | Google Doc

Beats by _______ - Rubric.pdf
File Size:	82 kb
File Type:	pdf

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