Food tests

The colours, the precipitate and the drop counts come from a teaching model, not from measured solutions. Real colours depend on concentrations: a weak glucose solution, for example, gives green or yellow with Benedict's rather than brick-red. The drop counts fix no DCPIP concentration; they only compare samples tested in the same way.

The 5 minutes in the water bath and the drops run faster than real time. The drawings of molecules are schematic, not to scale.