This paper presents an educational approach for teaching natural radioactivity using commercial
granite samples. A laboratory activity focusing on the topic of natural radioactivity is designed to
develop the knowledge and understanding of undergraduate university students on the topic of
radioactivity, to appreciate the importance of environmental radioactivity and familiarize them with
the basic technology used in radioactivity measurements. The laboratory activity is divided into
three parts: (i) measurements of the count rate with a Geiger–Muller counter of some granite samples
and the ambient background radiation rate, (ii) measurement of one of the samples using gamma ray
spectrometry with a NaI detector and identification of the radioactive elements of the sample, (iii)
using already recorded 24 h gamma ray spectra of the samples from the first part (from the Granite
Gamma-Ray Spectrum Library (GGRSL) of our laboratory) and analyzing selected peaks in the spectrum,
studen…