Video 1 shows a heat transfer experiment for flow over a flat plate. The plate is pasted with a liquid crystal sheet. The plate (seen in a plan view) is also initially heated and at a uniform temperature. Hence, the liquid crystal sheet appears blue. The experiment is started when air flow (from left to right) is initiated. The incoming air temperature is lower than that of the heated surface. At the same time, the heater connected to the flat surface is turned off. Under the influence of air flow, the surface cools with time. Owing to the formation of a thermal boundary layer, the cooling rate closer to the leading edge is faster than that to the right. Hence, the LCT sheet changes color from blue to red – first on the left side and then at the right.