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Jeudi 18 juin
The concept of force goes back to a time when forces were thrown out by deities (gods) to help or punish people, as in the old testament. Later, after Galileo and Newton, these became quantifiable scientific concepts, but still lacking in any coherent theory. Gravitational forces were confused with molecular forces, friction forces with heat and matter (caloric), and the concept of energy did not appear until the mid 1800s. The talk will review these old and modern ideas, but will mainly focus on how various forces or ’interactions’ have been measured and how this has lead to dramatic advances but also some spectacular blunders. The talk will end with a discussion of what is still not understood such as hydrophobic and dynamic (non-equilibrium, rate and time-dependent) interactions.