Chemical engineering concerns itself with processes and devices which convert raw materials into products by chemical or physico-chemical means. In this apparatus no actual chemical process is taking place. Nonetheless, it demonstrates a range of principles and tools relevant in chemical engineering: solution flow, airlift, flotation, gravity separation, pipes, valves, three- phase systems, sparging, froth formation, etc. While the inner workings of processes are mostly hidden to the observer, this apparatus demonstrates its principles visibly, allowing observation, contemplation and understanding – some of the core ingredients of scientific enterprise.