Giovanni Baliani

photo neededIn existographies, Giovanni Baliani (1582-1666) (CR:9) was an Italian mathematician, physicist, experimenter, lawyer, and senator, noted for []

Siphon problem
See main: Nature abhors a vacuum, Pump problem
On 27 Jul 1630, Baliani wrote a letter to Galileo Galilei about the explanation of an experiment he had made in which a siphon, led over a hill about twenty-one meters high, failed to work. Baliana attributed the fact that the pumps used to raise water at that time worked to the pressure of the earth’s atmosphere, but doubted that the total weight of an air column many miles high could be less than that of a thirty-foot high water column. [1]

“The higher we go in the air, the less heavy it is.”
— Giovani Baliani (1630), “Letter to Galileo” (note: in this letter, Baliani, supposedly made it clear that he believed a vacuum could exist, from the time he first knew that air had weight), Oct 24 [2]

Galileo responded with an explanation of the phenomena: he proposed that it was the power of a vacuum which held the water up, and at a certain height (in this case, thirty-four feet) the amount of water simply became too much and the force could not hold any more, like a cord that can only withstand so much weight hanging from it.

Mechanical equivalent of heat
In c.1635, Baliani experimentally demonstrated that by placing an iron pot filled with water on a spinning metal disk it was possible to make water boil. This experiment is said to have been one of the first references to an experimental determination of the equivalence between heat and work (mechanical equivalent of heat).

Associates
Baliani, from 1615 onward, was an associate of Italian physicist Galileo Galilei (and possibly also of Evangelista Torricelli ), and the two were said to have corresponded on scientific experiments and theories for over two decades. [1]

Education
Baliani seems to have been a lawyer and public office holder (governor and senator) by occupation, but a physicist by inclination. He appears to have occupied himself with questions of science from around 1612, when he was prefect of the fortress in Savona, where it struck him that cannonballs, although they have different weights, always fall to the earth at the same speed. At this time he also built a pot of iron that rotated in an iron vessel and that was so warmed by frictional heat that it was possible to cook inside it.

See also
● Giovanni Benedetti | Principle of inertia formulator

References
1. Baliani, Giovanni Battista – The Archimedes Project.
2. (a) Baliani, Giovani. (1630). “Letter to Galileo”, Oct 24.
(b) Galilei, Galileo. (1904). Le Opere de Galileo Galilei, Volume 14 (20 volumes) (editor: Antonio Favaro) (pg. 157-60). Barbera. (c) Middleton, William E. (1964). The History of the Barometer (pg. 9) (Amz). Publisher.

External links
Giovanni Battista Baliani – Wikipedia.
Giovanni Battista Baliani (Italian → English) – Wikipedia.

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