Infrared (IR), or radiation, thermometers are widely used in temperature measurements in many different sectors from health, food, automotive, agriculture, iron and steel to chemistry due to their fast measurement capabilities, reasonable prices, wide measurement ranges and ease of use. IR thermometers work based on black body radiation. In this experimental study, the accuracy of measurements made with IR clinical radiation thermometers and calibration systems were determined as a research subject. These became more important with the sudden expansion of the areas of use (schools, shopping malls, workplaces), especially during the epidemic COVID-19 period. The experiment gives students the chance to learn how to ensure the accuracy of the measurements of a measuring device used in daily life by doing their own experiments and it helps students understand how temperature measurements are carried out using the natural temperature-dependent emission of electromagnetic energy (thermal radiation).