Sunday, July 31

One of my favourite words, that I don't use enough, is ubiquitous. It's a good word with a very specific meaning but, to say it out loud sounds a bit pretentious.  However, one of the things in our society which has become ubiquitous is the humble tube, like the ones you get with toothpaste and so on.  Apparently, we've had them since the 1890's and Colgate claims the credit for introducing them to the market.

The first tubes were made of metal, a mixture of lead and tin and I don't want to think about the implications of putting something in my mouth which was stored in a container made of a lead alloy.  I can't find any evidence that this was a problem so maybe I'm just being over-cautious.  Anyway, it's rare to see a metal tube nowadays; plastic seems to have cornered the market.  

Years ago, Colgate introduced the toothpaste pump which they claimed was designed to 'solve the perennial problem - how to get the last little bit out of the tube.  And that's where the problem lies.

I buy a foot cream which comes in a tube and, in recent times, it has been. marketed in a fatter tube, apparently containing the same amount - 250gm.  Does the fatter tube make any difference?  Of course it does: that 'last little bit in the bottom of the tube' is a much bigger bit in the bottom of the tube.  It's all to do with a geometry.  If the smaller tube is 20cm in diameter, the formula to work out how much residue is left is 10x10 x pi x 5mm (say).  That is, the radius of the tube squared x pi x the depth of the residue.  

If the tube is wider (like my current foot cream tube), the formula is 22.5 x 22.5 x pi x 5mm.  Without working our the sums, the second tube secretes a residue more than 5 times the volume of the first.  If like most of the world, we chuck the tube out when we can't squeeze any more out of it, the manufacturer is making a little bit more profit.  We might like to think we are buying our foot relief product in a classier, more refined tube but, in fact, we're being ripped off by the manufacturer.

My advice to the men of the world who buy their foot cream in a modern fat tube: when you can't squeeze out another drop. cut off the bottom 3 or 4 cm of the tube.  You'll be surprised just how much you were about to throw away.