Comments on: Happy New Year with the Science of Champagne! http://blog.khymos.org/2006/12/31/happy-new-year-with-the-science-of-champagne/ - dedicated to molecular gastronomy Tue, 16 Apr 2013 09:36:17 +0000 hourly 1 http://wordpress.org/?v=3.5.1 By: Martin Lersch http://blog.khymos.org/2006/12/31/happy-new-year-with-the-science-of-champagne/comment-page-1/#comment-3406 Martin Lersch Tue, 30 Jan 2007 19:50:11 +0000 http://blog.khymos.org/2006/12/31/happy-new-year-with-the-science-of-champagne/#comment-3406 The friction force f = deltaP * pi * r^2 where deltaP is pressure difference between atmosphere and bottle and r is radius of cork. Hans-Uno Bengtsson considers the fact that the friction changes as the cork leaves the flask. He sets up an integral for the work which turns out to be one half times the friction force times the length of the cork. This rearranges to the following:

v = sqrt ((deltaP * pi * r^2 * l)/m)

where deltaP = 5 atm, r = 9 mm, l = 25 mm, m = 7.5 g. By converting to the SI units and inserting this into the formula, he gets an initial velocity of v = 20 m/s or 70 km/h.

]]> By: Eric C. http://blog.khymos.org/2006/12/31/happy-new-year-with-the-science-of-champagne/comment-page-1/#comment-2995 Eric C. Sun, 07 Jan 2007 12:55:59 +0000 http://blog.khymos.org/2006/12/31/happy-new-year-with-the-science-of-champagne/#comment-2995 I’ve performed he same kind of computation for the speed of a champagne cork (in french, sorry ; for those who can read it it’s here : http://eric.cabrol.free.fr/dotclear/index.php/2006/12/11/384-plop)
I find a velocity quite superior to the one you give here : 5 atm (relative pressure) on a diameter of 25 mm (area ~ 5 cm²) gives a force of 250 N.
Assuming a weight of 10g, the resulting acceleration is 25000 m/s².
After 0.002s the cork velocity is 50m/s, and it is only 5cm away from the bottle (so we can guess the pressure is still acting on it, although with rapidly decreasing intensity) …

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