Day 2 of 4--Engineering a Calorimeter: Designing and Testing a First Prototype
Lesson 8 of 11
Objective: SWBAT work within a small group to refine the design of a heat container that meets certain constraints as posed in a fictional business solicitation, and they will build and test a first prototype.
This lesson is number two of a four day process. The goal of this lesson series is to allow students the experience of testing materials, designing a prototype, testing it, and making modifications. The final product (in this case, a calorimeter) will then be used in a subsequent specific heat capacity investigation, LAB: What Metal Is This? Using Student Engineered Calorimeters in Lab.
In Disciplinary Core Idea ETS1.A, students are expected to define and delimit engineering problems, following specific criteria and constraints. This sequence of lessons exposes students to the engineering design process from start to finish.
During the calorimeter design process, students will need to test different materials to see which retains heat more effectively. This engages students in planning and carrying out investigations (SEP 3), analyzing and interpreting data (SEP 4), and designing solutions (SEP 6). Students are engaged in exploring thermal energy transfer and how to prevent it, addressing many core ideas in Disciplinary Core Idea PS3.B: Conservation of Energy and Energy Transfer.
Day Two involves introducing criteria and constraints to students, allowing the testing of the materials to determine the better insulator, and planning of a calorimeter design.
Materials needed for today:
- Styrofoam cups (small coffee size) *I typically buy 150 to be on the safe side for my 90 students working in threes
- Paper cups of an equivalent size *I typically buy 150 of these, too, although I always have a lot more paper cups than Styrofoam cups left over
- Thermometer (one per group)
- Access to hot water *I have a sink and microwave in my room, which makes this easy
- Scissors and tape for modifying the cups
Links to the other three lessons in this series:
Day 4 of 4--Engineering a Calorimeter: Modifying and Re-testing a Prototype to Inform Final Product Build
A fun way to introduce this activity is through a challenge presented by a fictitious company. The constraints and criteria for this engineering activity are given in this letter (what materials students may use and what the function of the product must be). Students are engaged in solving a problem within a real-world context, and will produce a calorimeter that they have to use in a specific heat capacity lab investigation later. The fact that students must use their own product means that they have a vested interest in building something fully functional.
I start this activity by projecting a copy of this letter and asking students to take turns reading it aloud. I pause at various points to highlight some of the more important information (up to 3 cups, paper or styrofoam, etc.). Then, I tell students that they need to group up in threes. If my class does not divide by three evenly, I allow pairs. I avoid groups bigger than threes because I want each student to have a voice in the final build of their calorimeter.
Once students have moved into their working groups, I handout Group Prototyping -- Heat Container. Then I direct students to spend a few minutes discussing and answering the first two questions. These questions are written to help students identify the constraints and criteria of this engineering challenge, even though the questions do not specifically use those terms. Students should articulate that they can only use a total of 3 cups, but they can be in any mix or match combination of paper and styrofoam. Students should also note that materials need to be able to be placed inside of and be removed from the heat container. Finally, the purpose of the product should be identified as preventing heat transfer between the contents and the surroundings.
At this point, before students begin developing their heat containers, they need to test their material options (paper versus styrofoam) in order to determine which one will retain heat better. I tell students to devise a method of testing the materials. If students are struggling, I will ask them questions to lead them to a viable method. I might ask, "How could we test if something retains heat?" in order to get students to answer that they would put something hot inside and see if it stayed hot. I also will suggest that students use water as their hot substance since I have a microwave in my classroom that they can use for heating the water. I will also recommend using a thermometer if students have not already retrieved them to use in their testing.
I only give students one of each type of cup for the testing. I also tell them that they cannot damage these cups in any way. Once they are making their prototypes, then they may alter them any way they see fit.
Students are also required to document their materials testing with a procedure, collected data, and analysis of that data. Based on their test results, each group will need to decide how many of each type of cup (up to a total of 3) they want to request for building their first prototypes.
Samples of Student Materials Tests:
Most students had results suggesting that styrofoam was better at retaining the heat, however, there were some groups who interpreted their results as showing paper as the better insulator. In the last sample shown above, the group's testing method most likely yielded inaccurate results since there was no real time-lapse between putting the water in the cups and taking the temperature. In the cases where students were concerned about their results, I suggested collecting more data, or, like the case previously discussed, I suggested changes they could make to their testing procedure. Regardless, students were encouraged to follow their data and decide what they thought would be best for using in their design.
As students completed their materials testing and wanted more cups for their prototype build, I asked that students bring their written materials testing documentation so I could make sure it was done. Then, I allowed students to trade in their testing cups and/or get additional cups for a total of 3 cups. Students needed to tell me how many of each type they wanted, then they could go back and work on their first prototype build.
I told students to complete the front of their group handouts BEFORE cutting or altering their cups and beginning their build. I also encouraged discussion and developing consensus before building. Students were given the rest of the class period to complete their first prototype. Groups that finished a build with time remaining were able to move ahead in developing a way to test their prototypes and to collect that data. Upon finishing testing, groups needed to propose modifications based on their data and rebuild. Rebuilds could get another 3 cups, any combinations again (not necessarily the same as the first), but could definitely NOT combine previous cups or parts of cups that would total more than 3.
Sample student work: