Scientifically, when was liquid pressure discovered?
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You are asking about the field of hydraulics. Knowledge and study of this goes back at least to ancient Greece. (It was Archimedes who, according to legend, solved the puzzle of the dishonest goldsmith when he submerged himself in his bath after puzzling over the problem for days, noted the water overflowing the tub, and ran naked through the streets shouting "I've got it!" Only he shouted it in Greek, so it came out "Eureka!" (As far as running naked through the streets goes, the Greeks took a more liberal view of such behavior than our present society. If you were to try that, you'd probably be chastised firmly.) \nBut I digress. Realizing that liquids are essentially incompressible, he was able to determine that the goldsmith was in fact a crook/Republican. From this humble start, modern hydraulic studies began.
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Through the discovery of nitroglycerin by two guys. \n\nNobel began experimenting with it until freak accident at a laboratory where he was working with nitroglycerin an explosion occurred, killing 6 including his brother.
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Oxygen was discovered for the first time by a Swedish Chemist, Carl Wilhelm Scheele, in 1772. Joseph Priestly, an English chemist, independently, discovered oxygen in 1774 and published his findings the same year, three years before Scheele published. Antonie Lavoisier, a French chemist, also discovered oxygen in 1775, was the first to recognize it as an element, and coined its name "oxygen"
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omg this 1 toootally got me!!\n\nhttp://www.liquidgeneration.com/content/a55hat.aspx?cid=316\n\njust scroll down n click "begin" ....boo!!
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The pressure that the substance is under. At room temperature for example, water can be ice, liquid, or steam, depending on the pressure of the room or container.
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DENIS PAPIS \nDenis Papin was famous in 1691 for the pressure-cooker ("digester") invention.\nHe had also invented the safety-valve to avoid the blast.\nIf the pressure on water differs from that of sea-level atmosphere, the boiling point is affected.\nAn increase of pressure outside the water raise the boiling point. The pressure cookers operate in this principle. Their steam-tight lids permit food to be boiled or steamed at temperatures higher than those can be obtained in an open vessel.\nThis is the reason of the more rapid food cooking
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One of the earliest attempts to explain the nature of water was made by the Greek philosopher Aristotle in 335 B.C. when he issued his Theory of Matter. According to Aristotle's theory, every substance was a combination of four basic elements—fire, earth, air and water. This idea was to keep alchemists busy for centuries trying to change common metals into gold by rearranging their "elements." They were not very successful, however, since no one was ever able to break down a substance and find out just how much fire, earth, air and water was in it. Not until the eighteenth century did scientists decide that air, earth and fire were not really elements at all, and in 1781 a British chemist proved that water wasn't an element either.\n\nThat year Joseph Priestley exploded a mixture of air and hydrogen in a bottle as "a mere random experiment to entertain a few philosophical friends," and noted with interest that the explosion caused moisture to condense inside the bottle. He repeated the experiment until he was certain that the moisture was produced from the reaction of air and hydrogen, thereby proving that water, rather than being a basic element, was itself composed of other chemicals.\n\nIn 1783 the French chemist Antoine Lavoisier elaborated on Priestley's experiment and discovered that the hydrogen was not combining with air to form water, but only with the oxygen in air. Further experiments determined that a molecule of water contained two atoms of hydrogen and one atom of oxygen, a chemical combination which has been given the symbol H2O.\n\nThe discovery that water was H2O or "hydrogen oxide" raised more questions than it answered, for chemists learned that despite its apparent simplicity water is actually a most puzzling and paradoxical substance which seems to defy the rules of chemistry.\n\nCompared to other liquids, water requires a great deal of heat to raise its temperature even a few degrees, and once it is warm it loses its heat slowly. This ability to "store" heat enables water to modify the world's climate. Oceans don't warm up as fast as the coastlines they touch, nor do the)' cool off as fast, with the result that coastal areas usually have milder winters and cooler summers than areas inland. For example, Bismarck, North Dakota has average temperatures of 8 degrees in January and 70 degrees in July, while Seattle, at the same latitude, has averages of 41 degrees and 66 degrees for the same two months.\n\nWater is the only substance found abundantly in all three natural forms—liquid, solid and gas. But in changing from one form to another some more peculiarities become evident. One of water's most paradoxical qualities is that when it changes into a solid it expands (and so becomes relatively lighter for its volume). Other substances, with the exception of bismuth, contract or condense and so become relatively heavier. Of course, if water condensed when it froze the world would have some serious problems. Ice would form on the bottom of a lake because it would be denser and therefore heavier than the liquid water. And there it would stay, growing upwards, killing all marine life. Underneath the surface, shielded from much of the sun's heat, very little of it would melt in the spring and eventually the rivers, lakes and seas in cooler parts of the world would become solid ice.\n\nThe world would have different but even greater temperature problems if there were no water vapor in the air to absorb the sun's heat during the day and retain it during the night. Daylight hours would be miserably hot, and nightfall would bring freezing temperatures. In southern states where winter crops are grown, farmers dread a cold, dry, clear night for this same reason. Without clouds and moist air to act as insulation, the earth's heat quickly escapes, permitting the temperature to drop unusually low and sometimes ruin citrus fruit and tender pl
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it's not that easy to define a "liquid" in a conventional way: take for example the glass for windows, it has its own volume and shape so we would define it a solid, but its microscopic disordered structure would make us call it a liquid! If we could wait ages we would see it flowing (as they say it happens for the windows in Chartres Cathedral.\nSo in material science liquid is a system that on ordinary observation time scale (years) shows a viscosity (the property of flowing  eg water is less viscous than honey) below 10^12 Pa*s
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Hydrogen was first produced by Theophratus Bombastus von Hohenheim (1493–1541)—also known as Paracelsus—by mixing metals with acids. He was unaware that the explosive gas produced by this chemical reaction was hydrogen. In 1671, Robert Boyle described the reaction between two iron fillings and dilute acids, which results in the production of gaseous hydrogen.[3] In 1766, Henry Cavendish was the first to recognize hydrogen as a discrete substance, by identifying the gas from this reaction as "inflammable" and finding that the gas produces water when burned in air. Cavendish stumbled on hydrogen when experimenting with acids and mercury. Although he wrongly assumed that hydrogen was a compound of mercury—and not of the acid—he was still able to accurately describe several key properties of hydrogen.\n\nAntoine Lavoisier gave the element its name and proved that water is composed of hydrogen and oxygen. One of the first uses of the element was for balloons. The hydrogen was obtained by mixing sulfuric acid and iron. In 1931, Harold C. Urey discovered deuterium, an isotope of hydrogen, by repeated distilling the same sample of water. For this discovery, Urey received the Nobel Prize in Chemistry in 1934. In the same year, the third isotope, tritium, was discovered. Because of its relatively simple structure, hydrogen has often been used in models of how an atom works.
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When push squeeze the bulb (this is the force), you exert pressure EVERYWHERE in the dropper, (upwards, downwards, etc), so the liquid in the medicine dropper it forced to come out since in the increase in pressure is applied everywhere,\n\nThis is known as pascal's principle
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I would visit the site cited below.  The discussion includes:\n\n"Irving Langmuir developed a way to measure vapor pressure \nby measuring the evaporation rate, which we will now flip around backwards. His reasoning is that the rate at which molecues are lost due to evaporation to a gas with no partial pressure of the evaporating substance is the same as the rate at which molecules of the substance would hit the surface if it were in equilibrium with the vapor (because in equilibrium the evaporation rate and re-condensation rate cancel each other out). His expression is: \n\n(mass loss rate)/(unit area) = (vapor pressure - ambient partial pressure)*sqrt( (molecular weight)/(2*pi*R*T) ) "
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1839\n\nhttp://www.uh.edu/engines/epi1476.htm
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Water potential is the tendency of water to move from one place to another. It is typically measured in units of atmospheric pressure: pascals or pounds force per square inch or bars or dynes per square centimeter. It is a measure of the ability of a solution to absorb water by osmosis.
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Better to visit this site for more details!!!\nhttp://www.ntvcelticfanzine.com/history%20corner/history%20coronation%20cup%20final.htm
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You better read something on this:\nhttp://en.wikipedia.org/wiki/Pressure
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stated the first version of the Law of conservation of mass, recognized and named oxygen (1778) as well as hydrogen, disproved the phlogiston theory, introduced the Metric system, invented the first periodic table including 33 elements, and helped to reform chemical nomenclature, not to mention where Mrs. Lavoisier's erogenous zones were.
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Liquids expand when they freeze.