It is not immediately obvious but the "magic" chemical gardens sometimes available as novelties are related to osmosis!

In these chemical systems the liquid component is a solution of sodium silicate (also known as "water glass" and "egg keep", owing to its tendency to form glassy deposits when dehydrated and its use historically as a method of preserving eggs by sealing the pores in the shell).

Most metal silicates are not very soluble but they begin their existence from solution as gelatinous precipitates which harden over time. When crystals of colored transition metal compounds are dropped into a sodium silicate solution some dissolving takes place at the surface of the crystals initially. The freed ions then form a gelatinous layer around the crystal with the silicate ion.

This layer behaves as a semi-permeable membrane. Water can get in but the ions cannot get out (hence the solution remains colorless). Because the slightly dissolving crystal under the gelatinous membrane creates a fairly concentrated solution compared to the solution outside the membrane, osmosis begins, driven by the entropy of dilution that will ensue if only the water can get through the membrane to dilute the dissolving crystals!

As water flows into the little membrane "sacs" surrounding the crystals, more dissolving occurs and more gelatinous precipitate forms AND the membrane begins to stretch. The crystals appear to "grow"!

The process pictured in the video clip took about 15 minutes of real time. Eventually the silicate structures harden and osmosis stops.