Year 13 Chemistry class are investigating aqueous systems, starting with solubility and coming to grips with the idea that really nothing is totally insoluble.

Firstly they made a powdery yellow precipitate of lead iodide which is generally considered insoluble. However, when heated it will redissolve showing the reaction must be in equilibrium and some ions still dissolved in the water. As the solution starts to cool, lead iodide crystals form and swirl around the tube, causing the golden rain effect. Thanks to Jazmin Davidson and Sam Atley, photographer and model respectively.