Thermal Paper as a Polarity and Acidity Detector
Dean Campbell | Thu, 10/28/2021 - 14:09
Thermal paper such as that used for point of sale receipts typically functions by darkening when exposed to heat. The pigment system used in this paper also darkens when exposed to solvents of intermediate polarity and acids. This enables thermal paper to be used as an inexpensive sort of indicator paper for a variety of demonstrations.