The final method discussed, is the Hot Disk Method. Also known as the Transient Plane Source Method, it is used to measure a material’s thermal diffusivity, thermal conductivity, and specific heat capacity. ASTM D7984 and ISO 22007-2 specify requirements of the apparatus and procedure. To perform the test, an electrically conductive flat sensor with protective film encapsulating it is sandwiched between two identical slab-shaped test samples. This sensor acts as both a heat source as well as a monitoring device, recording the time dependent temperature increase. Once sandwiched, a constant current is applied to the sensor which generates heat, and the thermal properties of the two testing samples can be determined by monitoring the temperature versus time. Since the temperature increase of the metal sensor is highly dependent on the two testing samples’ diffusivity properties, the resulting temperature curve yields the thermal conductivity, thermal diffusivity, and specific heat capacity through a series of calculations. This method does not reflect how Chomerics’ materials are used in applications, which is the main opposition to testing per this standard.