Model solves mystery of unique chemical garden growth

An unusual mathematical model has recreated the intricate crystal growth patterns of chemical gardens, finally explaining how these beautiful, lifelike structures form.

These intriguing formations of inorganic crystals have fascinated scientists for hundreds of years and the chemical reactions which create these precipitates are well-understood. ‘When you drop a metal salt crystal into a solution of sodium silicate – also known as waterglass – it starts to dissolve. This forms a thin skin around the crystal, mostly made of insoluble metal hydroxides,’ explains Oliver Steinbock, a microstructures chemist at Florida State University, US. ‘Meanwhile, osmosis is at work, pushing water through this semi-permeable membrane. This building pressure eventually causes small breaches, which shoot out a jet of salt solution. Around these jets, the tubes of our chemical garden begin to take shape.’