vasos comunicantes
English translation: communicating vessels
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| 01:24 May 24, 2003 |
| Portuguese to English translations [Non-PRO] Science - Physics / physics, elementary | ||||
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|  Selected response from: Michael Powers (PhD) United States Local time: 02:01 | |||
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| Summary of answers provided | ||||
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| 4 +7 | communicating vessels |
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| 5 +3 | communicating vessels |
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| 5 +3 | Communicating vessels |
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Answers
3 mins confidence: 
peer agreement (net): +7
peer agreement (net): +7communicating vessels Explanation: straightforward -------------------------------------------------- Note added at 2003-05-24 03:32:58 (GMT) -------------------------------------------------- This apparatus is to illustrate the principle of communicating vessels. It consists of three pieces of glass, two of these being cylindrical tubes with different interior diameters, mounted on a wooden base, with different inclinations. These tubes communicate with each other by a brass tube seated on the base. A receptacle with the shape of an inverted bottomless bottle is positioned between the two tubes and communicates with them through the same brass tube. Any of these three pieces of glass fit into the three openings of the brass tube, the junctions being sealed with sealing wax and beeswax. A ring of brass is fixed to the upper part of the central vessel. From Colégio dos Nobres, catalogue n.º 214. \'s Gravesande, Physices Elementa, Leiden, 1742, Vol. I, p. 1424, Tab. XLVII, Fig. 2. Physics Fair Experiments 33. Communicating vessels (water-hose) When water is poured into a U-shaped water-hose, the water reaches the same height on both sides. This result is generally expected. Now the hose is wound up a few times around a reel. Water is poured into one end of the hose. Observe how the water level is different on both sides. Explanation 1: . Think about that and you will understand how you can pour tea out of a teapot! When the pot is tilted sufficiently, the level of the tea in the nozzle exceeds the edge of the nozzle. Then the tea is poured out. The wound-up hose forms no real communicating system, because some air is locked in. Explanation 2: According to the law of the \'communicating vessels\' the levels in both legs of the U-shaped water-hose are the same. The water has free contact between the two vessels, and the same (atmospheric) pressure is exerted on both surfaces of the water. When water is poured into the wound-up hose, this law of \'communicating vessels\' will hold for as much as the first half loop of the hose is completely filled with water. When more water is poured in, the water will flow over the highest point of the loop and it will settle at the bottom of the next loop. At this moment an amount of air is locked up in the second half of the loop. When more water is poured in, that amount of air is compressed. One needs more pressure (higher water-column) of the water that is poured in, to let the water pass the first loop. The same holds for the next loops. -------------------------------------------------- Note added at 2003-05-24 03:37:23 (GMT) -------------------------------------------------- FREEZE THE MELTING Because of global warming, ice caps melt and sea levels rise. This seriously threatens lower countries like the Netherlands. Communicating Vessels invites you to participate in the \"Freeze the Melting\" project. In the Waterline Tours box you will find a U.S-NL solidarity flask. This flask contains a sample of non potable New York Bay water. We request you to place it in your freezer for a period of at least fourteen days, thus returning the sea water to its former frozen state. With this symbolic gesture, you assist in delaying the consequences of the world\'s changing hydrographic balance. By doing so, you express your solidarity with the people of the Netherlands. All participants receive an official record, confirming their participation. A duplicate of the document will be send to Queen Beatrix of the Netherlands. You will find the required forms in your Waterline Tours accessory set. -------------------------------------------------- Note added at 2003-05-24 03:41:29 (GMT) -------------------------------------------------- Quando dois líqudos que não se misturam (imiscíveis) são colocados num mesmo recipiente, eles se dispõem de modo que o líquido de maior densidade ocupe a parte de baixo e o de menor densidade a parte de cima (Figura 1) . A superfície de separação entre eles é horizontal. Por exemplo, se o óleo e a água forem colocados com cuidado num recxipente, o óleo fica na parte superior porque é menos denso que a água, que permanece na parte inferior. Caso os líquidos imiscíveis sejam colocados num sistema constituídos por vasos comunicantes, como um tubo em U (Figura 2), eles se dispõem de modo que as alturas das colunas líquidas, medidas a partir da superfície de separação, sejam proporcionais às respectivas densidades. Na Figura 2, sendo d1 a densidade do líquido menos denso, d2 a densidade do líquido mais denso, h1 e h2 as respectivas alturas das colunas, obtemos: d1h1 = d2h2 Exemplo: Demonstre que líquidos imiscíveis colocados num tubo em U se dispõem de modo que as alturas, medidas a partir da superfície de separação, sejam inversamente proporcionais às respectivas densidades. Resolução: A pressão no ponto A é igual à pressão no ponto B (mesma horizontal e mesmo líquido): pA = pB Mas: pA = pATM + d1gh1 pB = pATM + d2gh2 Assim: pATM + d1gh1 = pATM + d2gh2 d1h1 = d2h2 Exercício: A figura representa um tubo em forma de U aberto em ambos os extremos, contendo dois líquidos, A e B, que não se misturam . Sendo dA e dB, respectivamente, as densidades dos líquidos A e B pode-se afirmar que (A) da = 1,0 dB (B) da = 0,8 dB (C) da = 0,5 dB (D) da = 0,3 dB (E) da = 0,1 dB -------------------------------------------------- Note added at 2003-05-24 03:43:58 (GMT) -------------------------------------------------- Vasos vasos.exe (0 kB) Este programa representa um sistema de dois vasos comunicantes contendo líquidos. A idéia é estabelecer uma analogia do fluxo de água com a corrente elétrica. O nível dos líquidos representa a voltagem, o tubo entre os vasos representa o condutor. Diversos parâmetros podem ser variados para se observar os diferentes efeitos. A resistência, a capacitância, a corrente e a tensão elétrica são alguns dos conceitos estudados. |
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