Differential Scanning Calorimeter

  •     Our differential scanning thermal analyzer uses phase changes to identify unknown materials. It applies heat to two chambers: one with a substance and the other empty, and measures the temperature in the chambers. By comparing the graphs and identifying spikes in temperature, you can tell what the sample is made up of. For example, a sample of water might show a temperature spike at 100˚C, or paraffin wax might change states at 25˚C. A mixture would show spikes at both locations. The tool can be constructed from materials accessible in Rwanda, and the cost in the US was well under $50. Other thermal analyzers of this type start at $20,000, so ours is 1/400 the cost of its next­-lowest competitor. It requires only simple tools: a toaster/Nichrome wire, clay, electricity, and tape that can withstand high heat. We are hopeful that, in Rwanda, our device will assist in improving chemistry labs.

  •     In this studio, our goal was to create lab equipment out of inexpensive and accessible materials and objects for a lab in Rwanda. Our project focused on creating a differential scanning calorimeter/thermal analyzer. This is a device used in chemistry experiments to analyze thermal properties of a given material.

        The device heats two chambers (one holding a reference material, one holding the material to be analyzed), then takes the temperature of those materials as they go through state changes. 

        During the first few days, we focused on the heating aspect of a differential scanning calorimeter. Initially, we thought that a clothing iron would provide the type of heating components we wanted; it could get extremely hot, and it's accessible in Rwanda. Our first concern with the clothing iron was that it wouldn't provide even heat. This is important because the amount of heat given to the two chambers must be even or else the experiment is invalid. We tested this by placing two cups of water (in Pyrex) on the front and back of the iron and timed the boiling point. However, there was a very clear problem: the water did not boil. We figured out that the Pyrex cups were too heat resistant and wouldn't allow the water to boil. However, when we got the temperature of the actual iron, we also saw that it was hot, but not as hot as we needed. Our goal temperature was 300 degrees Celsius.

        At this point, we started looking at other possible devices that we could take apart and use for our project. We decided to use Nichrome wire which is found in most devices that heat up, especially toasters. We were able to combine this Nichrome wire with metal struts, frequently used in construction, and clay for thermal insulation. This equalizes the heat coming into the chambers but keeps them thermally isolated. We built this thermal chamber and wrapped it with the heating panels from a toaster. In an early iteration, the panels would sometimes touch and short­-circuit. For our final iteration, we layered clay between the panels. This solved the problem entirely.

        In our final iteration, we also lengthened the wires to the heating circuit, raised the entire differential scanning calorimeter above the ground, and used color-consistent clay.