Math O' Man : The Blog of Mathematics

Compression of a soccer ball




Today is the finale of the soccer world championship and the last opportunity ta ask my reader the following question:

When a player receives a ball on his head, the ball is compressed for a very short moment before it is bounced back. Have a guess, what is the maximal deformation of the ball (in cm)?

Here are some measures about the soccer ball according to the rules of the FIFA: it is of spherical shape, made with leather or similar material and has, at the beginning of the match, a circonference between 68 and 70 cm, a weight between 410 and 450 g and a pressure between 1,6 and 2,1 atm (1600 - 2100 g/cm²).

Mixing wine and beer


Before summer I wrote a blog entry about mixing wine and beer. french friends told me that such a mixture can't exist, putting beer into wine is a sacrilege... It is okay to drink one after the other, but never, never simultaneously! The order though, wine first or beer first, depends on the contry:
Germany: Wein auf Bier das rat ich dir, Bier auf Wein das lasse sein.
France: Bière sur vin est venin, vin sur bière est belle manière.
England: Beer after wine, and you’ll feel fine, wine after beer and you’ll feel queer.
So I was very suprised when during summer brazilian friends introduced me to espanhola, a drink that they like to mix on the beach and which contains exactly wine and beer! The taste depends on the proportions (mostly more beer than wine), the color looks rather dirty and flakes swim around in the glass...

Those brazilians mix...
...wine with beer!

Sophisticated rhythms perfectly performed


Short musical interlude — or rather a machine interlude since these guys look like tin soldiers and play the most complex rhyhmical patterns with the precision of a swiss watch. The drum group Top Secret Drum Corps from Basel is extremely precise, on a local and on a global level.



Just for comparison a video of the brazilian Batucada or Bateria Batala, where I played the Caixa (snare drum) for some years. We don't have the same precision as the swiss but nevertheless a lot of fun ;-) Viva la Samba in Paris!

At the beginning of the video clip there ere only the repiniques and the caixas, the girls in the first row start join in later with another rhythm on their big drums called surdos.