George Lisensky from Beloit, WI United States
These models are wonderful for illustrating the NaCl structure and the cleavage that occurs if you shift the ions by one position. Actual NaCl crystals do the same. We use water softener salt and have students do the experiment.
These models are one of the few molecular models that get the energetics correct. Forming a bond releases energy but most models leave the impression that energy is required. When we first talk about bonds I pass out a pair of atoms to each student and have them experience bond formation as a kinesthetic experience. Its worth the clicking distraction to have them form bonds over and over!