7. How to make a Torrichellian barometer Torrichelli proves the existence of a vacuum. When he tilts the tube the mercury fills the tube. When he raises the tube to upright, the mercury falls to 760 cm leaving a vacuum above. A portrait of Torricelliās mentor, Galileo, hangs on the wall Torricelli with his newly invented barometer In Italian, āTorreā means ātowerā. So, Torricelli means ālittle towerā.
31. How to read a manometer Comparing barometer to manometers:
32. Absolute pressure vs. Relative pressure (Gauge pressure) We must use absolute pressure readings (and absolute temperature readings) in using the gas laws. Otherwise, our equations our equations become as complex (and even more complex) as the original Charlesā Law.