This paper describes a set of demonstration school experiments where infrared radiation is detected using thermal sensitive foils. The possibility of using standard glass lenses for infrared imaging is discussed in detail. It is shown that with optic components made from glass, infrared radiation up to 2.5 µm of wavelength can be detected. The effect of surface emissivity is studied qualitatively where in different experimental arrangements lower or higher detected irradiance from a low emissivity surface can be obtained.