Pouring coffee, thermogram footage. Thermography records the temperature of surfaces by detecting long-wavelength infrared radiation. The colours show variations in temperature. The scale runs from white (warmest), through yellow, orange, red and purple to blue (coldest). This footage shows hot coffee (bright yellow) being poured into a cup. The cup radiates the heat from the coffee, turning bright yellow as well. The cup has a holder that is cooler and made of insulating material (purple).