Institute and Museum of History of Science, Florence, ITALY

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Magical inflations The feather and the guinea The void: an absurd idea

Experimental apparatus for the fall of weights in the vacuum.
Jean Antoine Nollet, Leçons de physique expérimentale, Paris1743-1748



Galileo was the first to claim that bodies, whatever their material, weight and volume, all fall at the same speed. Experimental proofs showed, on the other hand, how heavier bodies hit the ground well before lighter ones.
Thanks to the completion of instruments which easily produced the vacuum, at the end of the seventeenth-century, an ingenious experimental device was constructed which finally made it possible to show that Galileo was right. A feather and a gold coin (an English Guinea) were made to fall simultaneously in a glass tube which had been emptied with an air-pump. The two bodies, despite their differing weights, reached the bottom of the tube together.




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