When you swoosh your hand through the air, if you happen to knock against a fixed and solid object like the book-case or the door, you are made aware of the fact that the space through which you intended to swoosh your hand is already occupied. The book-case is solid, and dense, and refuses to get out of the way unless you apply a far greater force than you are prepared to exert by knocking it with your hand. The same idea, less painfully learnt, holds for a blow applied to water, though if you bang your hand down hard and flat on the surface of the water, the resistance will be sufficient to cause your hand to sting, although some of the water does fly out of the way.
The University of Sydney acknowledges that its campuses and facilities sit on the ancestral lands of Aboriginal and
Torres Strait Islander peoples, who have for thousands of generations exchanged knowledge for the benefit of all.
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