Chameleon bubbles are formed when a sodium alginate solution is dropped into a calcium chloride solution.  The bubbles are filled by an acid‐base indicator solution; so, adding the beads to acids or bases leads to colour changes inside the bubbles by diffusion and pH change. Students can learn about acids, bases,...

The chemical garden is a well‐established experiment from the chemistry of salts, solubility, diffusion, and solutions. The nice thing is that if metal salts are put in sodium water glass solution, it can lead to an effect reminiscent of plants growing. This growing process can be observed and analysed. In the end...

Gelli Baff, a crystalline powder, has been dumped into a bathtub filled with water. How can you force the hydrogel to go down the plughole in order to drain the bathtub? 

In this investigation, students learn about swelling reactions, balanced reactions, and polymerisation. Students should be able to...