As tiny particles like protons and neutrons can be observed very difficultly, it is better to construct some scale models reproducing the atomic and molecular system so that the mass of the elementary particles can be displayed. Therefore this kit consists of some little balls used to realize three separate series of scale models, with different mass. Each series have the same atoms or molecules; only the mass of the little balls simulating the proton and the neutron is different. This kit enables to understand that the atomic or molecular mass (expressed in grams) corresponds to a quantity of matter containing a constant number of little balls; the value of this constant only depends on the mass of the particular little ball used to realize the scale models. Thus the theoretical value of Avogadro’s number can be determined.
Series of scale models:
THEORETICAL – EXPERIMENTAL HANDBOOK