The First Person to Weigh the Atmosphere

Italian Jesuit Evangelista Torricelli was able to definitively prove that the atmosphere has a specific weight by designing an experiment in which a tube is filled with mercury and then placed into a dish of mercury. Torricelli disovered that when performing this experiment, half of the mercury runs down into the dish and the other half stays within the tubing. Until this point, it was believed impossible to create a negative or empty space as the Ancient Greek philosopher Aristotle once stated, “nature abhors a vacuum” believing that nature would forever fight against the creation of true and pure nothingness. This is the same reason that an object (e.g. plastic straw or an oil drum barrel etc.) crumbles when all of the air within is extracted. Torricelli was able to overcome this phenomena by using the exteme weight of mercury within a ridged glass tube. The level of mercury left within the tube was a measurement of the weight of the atmosphere, a balancing act between the weight of the mercury and the weight of air pressing down upon this mercury, balancing each other out like scales. Torricelli famously stated, “noi viviamo sommersi nel fondo d’un pelago d’aria” which means “we live submerged at the bottom of an ocean of air” in Italian, and his findings made scientists realize that air was a substance for the first time. Torricelli became the first person to invent the barometer because of his understanding of atmospheric pressure. Despite Aristotle being believed to be correct for millennia, Torricelli definitively proved that air does have weight

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