Timelapse footage of the results of the Tollens' test for the presence of aldehydes. In the Tollens' test, the solution to be tested has ammoniacal silver nitrate added. In the presence of an aldehyde, the diamminesilver complex oxides the aldehyde to a carboxylic acid, reducing the silver ion to silver metal, which precipitates out of solution, forming a so-called silver mirror on the glass of the flask.