Having just been down to New Orleans or Nawlins (check out Captain Beefheart and His Magic Band’s pronunciation on the classic track Click Clack – I bought the album long before most of the readers were born!) for an ASTM E56 Nanotechnology meeting, my thoughts naturally turned to my next visit when Pittcon 2015 will be there (March 8 – 12, 2015: Ernest N. Morial Convention Center; New Orleans, LA USA. See: )
Yawl probably all recall the competition that we ran on our stand – guess the number of candies in the container and win a $500 AMEX card. As Tom Guenette gave the correct number (10159) in his blog then there’s little point in telling you the right number again …
You may have seen my last blog on Fermi problems . How did I fare when I tackled this one?
Several guesses. Being that we were in the United States and that the ‘cylinder’ was around 12 inches in diameter and 12 inches high made me reason that it was a 2 gallon container (or ~ 7.57 liters for our friends on the East side of the pond). Mixing units, as scientists do (except when landers have to make it to Mars…) the balls appeared to my eye to be around a centimeter in size (or maybe 3/8 inch US?) meaning that the volume of a single candy was around 0.523 units (pi/6 times diameter). Now chemists will have dealt with packing of spheres probably in their first year at college. It goes back to the efficient packing of cannonballs (didn’t we have a single cannonball in the last blog?). Obviously with cubes and other shapes such as square plates then one can pack without voids). The most effective packing schemes (face centered cubic and hexagonal close packing) for spheres is ~ 74% (pi/18 or pi/3√2 for the math experts) so let’s assume that we can’t pack that well in our 2 gallon container – take a guess at 70%.
So we have for our 2 gallon container 0.7*[7570/0.523] = 10133 spheres. Remarkably close to the true result of 10159…. One problem at the time – I tried to be too smart and used 3/8 inch and came up with 9424 – still within an order of magnitude but my ‘smartness’ put me further away… I also measured the volume of the container by filling it with water when it was returned to Malvern Inc. at Westborough – it’s actually 9 liters so closer to 2 Imperial Gallons….. So the sphere packing is actually less efficient than 70%…. You can work that one out for yourself – the real packing density. Scott Krane’s kids had eaten all the candy, so I don’t have one to measure with a vernier. Were they actually 3/8 inches or were they 1 cm? The problems scientists face…
What will we have as a customer magnet next year at Pittcon? You’ll have to wait and see!
Right now, you can check out details of the five short courses we are running at the Pittcon 2015 and start dreaming about sunnier climes (well, – at least it’ll be warmer than Chicago).
March 9 2015: Fundamentals of Particle Size Analysis with an Emphasis on Light Scattering Techniques with Alan Rawle & Ulf Nobbman
March 10 2015 (PM): Sampling for Particle Size Analysis with Alan Rawle
March 10 2015 (PM) Particle Size and Zeta Potential Characterization of Nano Particles with Anastasia Morfesis
March 12 2015 (AM): Separations: Fundamentals of Advanced Gel Permeation and Size Exclusion Chromatography Detection with Ulf Nobbman
March 12 2015 (PM) Optical Rheology: How to use Light Scattering to Obtain G’ and G” from the Mean Square Displacement with Ulf Nobbman
We look forward to seeing you there!