Parabolic Solar Cookers

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I am excited for our final project in Algebra II…parabolic solar cookers! After we did an in class investigation of the four different types of conics with play-doh, evaluated the standard equations, and explored the graphs of each, I wondered if there was one more way I could help my students deepen their understanding of conics. So, while sitting on the couch at home with my husband and searching online, I found this ( and excitedly told him, “I’m going to make this happen!!” The next day at school, I talked with my dean about the logistics of creating solar cookers and ways to help scaffold the lesson.

The summary of the project and the student materials that I revised from the website are below (some wording and pictures are directly from the website above…so please credit that source if using this.) The directions are quite lengthy, but very step-by-step, so I suggest breaking this up into at least 3-5 days with groups of 2-4 students.

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Summary: To begin the project, students spent a class day researching and answering questions about solar cookers. With the help of an actual solar energy engineer (see his website and work here: generating some ideas, the questions helped students buy in to the project (he also sent me some videos to show students real life parabolic solar panels…if you have Dropbox, check them out here: The next day, students found three points to create a parabolic curve based on the dimensions of their shoe box (two top corner points and one center origin point). From these, students calculated the equation and plotted other points to create a nice, accurate curve. Next, students calculated the focal point, which we talked about the reasoning as to why this is the spot they should place their food at to cook. Lastly, students covered their curves in poster board and foil for the reflective surface and fashioned holders for the focal point.

A few groups still need to finish, but they are coming along very nicely! It has been raining/cloudy for about a week straight now, so please do a little anti-rain dance for us and hope for some sun so we can test out these cookers before the school year ends!! I will post after we get to and show the results!solar 5

Student Materials: (link to word doc: solar cooker proj or click on thumbnails below for images)

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Update: We finally had some sunny weather and got to go out to cook. We left the solar cookers out for about 45 minutes. The marshmallows didn’t melt the way we predicted, but having thermometers out with us proved that it definitely got hotter at the focal point. Most had an initial temperature of 90-92 degrees F, and after about 20 minutes, the temperature rose to about 105. The final temperature recorded was about 120 degrees F at the focal point of most solar cookers. Although they were a little bummed that the marshmallows didn’t melt completely, we talked about the fact that if it were 120 degrees F outside, they would not want to be outside themselves. So, that helped put it in perspective and see that it worked. Next year, I think we should try cooking a darker food substance…maybe chocolate, and we could do fondue 🙂


Nuclear Culture

We just finished a 3 week long interdisciplinary unit on nuclear energy. I am very grateful to have the opportunity to work with the same core sophomore teachers for the past three years. We have grown together personally which I think in turn has had a positive effect on our students learning (supported by The Washington Post here), and we have also accomplished a lot professionally together. We started out three years ago trying to become more unified in our teaching approaches with simple ideas like wearing the same t-shirt on the same day. Needless to say, that wasn’t quite an authentic learning opportunity for students. Our approach evolved into us using the same vocabulary word somewhere in our dialogue throughout the week in hopes that our students would catch on and use it for their “personal dictionary” assignment in English. I definitely learned a lot of new words, but again, this was such a simple daily act and we knew we could do more!

Featured imageWith the help of our Trinity University interns a couple years ago, our most unified approach was created- a UbD unit centered around nuclear chemistry with lesson plans in English, world history, geometry, and Algebra II. (I have to plug an incredible master’s program here that prepares student teachers with a high level of understanding about teaching pedagogy and practice). This unit has gone through three years of revision and I have to say, the way in which everything came together this year, I think it was the our best year yet!

The first year we did the project we were not able to incorporate math because it did not fit with the scope and sequence. I still remember hearing one student mumble, “you know, we’re studying nuclear energy n every subject except math.” My heart sank and I knew I was going to find a way to make it happen! The next year, I decided to switch the sequence of our curriculum and teach exponents at the beginning of the spring semester when the nuclear culture unit started. Working with my Trinity intern that year, we created investigative lesson plans where students discovered how radioactive elements decay. Understanding asymptotes also helped students see that nuclear waste will never reach 0. We then discussed the implications for using nuclear energy based on exponential growth and decay and exponential properties. This year, I added the geometry component and solidified the inclusion of math in the unit. After my students learned about proving congruent triangles, I went into the English/World History combined classes and introduced their persuasive essay by asking students to write an outline in a mathematical proof format (I was lucky to have another intern this year and she taught a great lesson on truss strength involving triangle properties this day while I was teaching in the other room…I’ll save that post for another day). I loved how the proof writing gave my geometry students the chance to be experts on the topic they just learned and were able to refresh the Algebra II students how to write proofs. Also, the English teacher loved the way they provided evidence for their essays and did some formulaic pre-writing before jumping on a computer to type their essays. Finally, after the culminating day of the project (a “town council meeting” to debate whether we should pursue nuclear energy in San Antonio), the World History teacher created a graph where the x-axis was labeled as a continuum from “San Antonio should not pursue nuclear energy” to “San Antonio should pursue nuclear energy” and the y-axis was a continuum with “the US should not pursue nuclear energy” to “the US should pursue nuclear energy”. Students then plotted their personal opinion as a visual representation for further dialogue.

My heart is full after this unit and I loved hearing quotes like this: “I like the way every class was included in this unit because we understood all perspectives.”Featured image

One of My Favorite Projects

Featured imageI am starting off blogging by sharing one of my favorite projects that I created with my dean a few years ago. After attending a conference at Southwest Research Institute, I got inspired to do a project that would help students connect their learning of quadratics to the real world. I decided to make it about projectiles. I dreamed of getting to launch projectiles across the math classroom, but had no idea how to make this possible. After talking with my dean who is essentially a physics guru, he helped my dream become a reality. Below you will find the process and some reflections on the project.

First, we modeled a projectile using LoggerPro software and found the quadratic equation. This equation became the central focus for our students to manipulate. We asked them to find the vertex form, x-intercepts, y-intercept, and the domain and range. The fun part came on the second day of the project. We hung tennis balls in the back of the room and gave each group (groups of 3-4 students) a different height at which they would set their equation to. Using the quadratic formula, they solved their equation for the x-distance at which to launch the projectile. If their calculations were correct, they would successfully hit the tennis ball. With safety goggles on, measuring sticks in hand, and genuinely excited emotions, each group stepped up to the projectile launcher to try out their solutions. Some chose to set the launcher at the farthest distance for more fun, and some chose to go the safe route and try the closer distance. Several groups hit the target on the first try which was so fun to to watch the teamwork of their groups as they high-fived and congratulated each other. The groups that didn’t hit the target on the first try realized they needed to watch for the human error of lining the projectile launcher up straight. By the end of each class period, each group had successfully hit the target and proved their math calculations correct.

I love this project because it’s an authentic way to check their work. Also, my first couple years of doing this, I connected it to space science by having a hook that the students were trying to blast a near earth object out of our orbit (Armageddon style). Two years ago, my sophomore team and I designed a full interdisciplinary unit on Nuclear Culture. So to connect it to this, I changed the theme up a bit and had students watch a video about NATO’s ballistic missile defense program and then act as if they were helping NATO use projectiles to intercept incoming harmful missiles. Students were able to communicate their reasoning behind advantages and disadvantages of using technology like this and what might happen if we were successful or unsuccessful in hitting their target. I loved that students made connections, communicated coherently, problem solved, and found reasoning and proof (all performance outcomes that the math department at my school tries to achieve) in one single project!

Here’s the link to the student materials: Saving the World with Math