Demonstrating close-packing of atoms using spherical bubble gums

In this paper, the use of spherical bubble gums (Gum Balls) to demonstrate the close-packing of atoms and ions is presented. Spherical bubble gums having distinctive colours were used to illustrate the different layers in variety of crystalline packing and the formation of tetrahedral and octahedral holes. Students with hands-on experience of building the different packing models could better understood the close-packing of atoms.