Figure 3. Visual pictures and thermograms show that glass is IR-intransparent (top) and that a metal surface can reflect IR-radiation (bottom)

From

Can You See the Heat? – Using a Thermal Imaging Camera in the Chemistry Classroom

Claudia Bohrmann-Linde, Simon Kleefeld

World Journal of Chemical Education. 2019, 7(2), 179-184 doi:10.12691/wjce-7-2-18