Talk:Pascal's barrel

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The claim that Pascal did this apparently crept into French physics education between about 1840 and 1860. I find this textbook of 1848, where "crève-tonneau" is given as a section title, but the text doesn't mention any historical experiment, it just repeats, with Pascal, that the force on the bottom of the container may become arbitrarily large. In 1863, I find a description of how Pascal was the first to do this, complete with stating that he attached a tube of a length of "about 10 meters" etc. I suppose this is just oral tradition between physics teachers, one made up an example problem, and the next generation took that for historical lore. It's nice to be able to tell when this approximately happened. The actual historical experiment relating to the principle is known as "appareil de Haldat"/"Haldat's apparatus".[1]

The problem in performing the experiment seems to lie in making the gasket connecting the tube to the barrel more pressure resistant than the barrel itself. This is almost impossible unless you purposedly weaken the barrel beforehand. So it seems this is little more than a thought experiment. I looked around on youtube, and I am sure if the experiment was at all feasible with realistic effort, there would be videos. As it is, all I found is a video by one guy who tried it and failed (hose from the top of a building), fortunately enough being honest enough to admit in the video description that he produced the burst of spray by shooting the bottle with a slingshot.

In this video I have taken a column of high density salt water an extra 15 feet over Pascals experiment, to a total of 50 ft. and shown that is is not even enough pressure to burst a structurally weakened milk container. The total pressure inside the container is fairly high, no doubt, but its not sufficient to cause it to burst. The height it would take to supply the necessary pressure of 120 psi to burst the jug would require doubling the distance, to 100 ft, which would have produced something doubtlessly spectacular. Although it is an interesting fact about pressure, the story remains to be proven. Added note, the spray that comes out just before the Dr. Strangelove montage is due to being shot with a slingshot, but does show that there was quite a bit of pressure due to only 8 ounces of water that filled the 50 ft. column.

..plus this rather underwhelming result in a physics class (height of just about 3 m, 'we didn't burst the barrel but it is bulging pretty substantially') --dab (𒁳) 20:25, 9 June 2014 (UTC)[reply]

Also, this delightfully eccentric Italian guy who has the hose suspended from a bell-tower in Albania for some reason while explaining the principle to a couple of nuns, but in the end he doesn't seem to try to burst the barrel and operates some kind of water-wheel instead. --dab (𒁳) 20:39, 9 June 2014 (UTC)[reply]