[In science teaching, and other aspects of elementary education] there is a time, much greater in amount than commonly allowed, which should be devoted to free and unguided exploratory work (call it play if you wish; I call it work). Children are given materials and equipment – things – and are allowed to construct, test, probe, and experiment without superimposed questions and instruction. I call this phase «Messing About.» […] In some jargon this kind of situation is called «unstructured,» which is misleading; some doubters call it chaotic, which it need never be. «Unstructured» is misleading because there is always a kind of structure to what is presented in a class […]. ~David Hawkins (Messing About in Science, 1965)