Part of the challenge of every subject at college is bringing the learning to life. It’s all very well reading about the formation of salt crystals in Chemistry, for example, but nothing beats seeing it happen in real life. Especially when the results are so beautiful!
Back during Science Week one of our students set up a series of crystal experiments, which have been slowly forming and taking shape over the ensuing weeks. Sodium chloride crystal experiments involve dissolving salt in hot water until saturated, then allowing the solution to evaporate and crystallise, forming salt crystals. As the water evaporates, the dissolved salt molecules lose their mobility and begin to arrange themselves into a regular, repeating pattern, forming the crystal structure.
Salt crystals are held together by ionic bonds between sodium and chloride ions, making them cubic in form. It is fascinating to see them develop both in the dish itself and along the string. The students have really enjoyed seeing how the solubility of salt decreases as the water cools, leading to the salt separating from the solution and forming crystals.
