Food, wonderful food!

Happy Thanksgiving.  The world population is at 7 billion. Oddly, you don't hear as much talk about overpopulation as we did in the 1970s when we were approaching 4 billion. We have passed a number of doomsday deadlines since. Seven billion and more is a drain on resources and probably the biggest problem facing the world, but why aren't we in more trouble already?

An increase in the population of, say, squirrels increases the survival prospects of the whole species. Beyond a certain point, too many squirrels means too much competition for resources, followed by a demographic correction. The sustainable number of squirrels is dictated by predators too.

But humans are already well beyond a sustainable number of berry pickers and stick fisherman. Medicine, agricultural and industrial advances have made impossible numbers of humans possible. Humans have also managed their predators. So here's an interesting notion:

The probability of the birth of a person who will develop a technology that makes a larger population possible is made greater by a larger population.

This is different than squirrels, for whom breeding is the sole mechanism for maintaining the species. Humans are increasing the odds of finding the next survival-enabling genius by creating a huge pool of (mostly) consumers.

Tin Whiskers

I think it's cool when a little bit of novel science or technology presents itself unpredictedly.  The Mandelbrot set was like that.  Tin whiskers are like that.  In response to environmental and health guidelines under the RoHS (restriction of hazardous substances) initiatives, the mix of metals in electronic solder has been changed to eliminate lead.  Electronic solder has had tin it for as long as I can remember.  However, the amount of tin has been increased and the mix has changed, and this has highlighted a behavior of tin alloys.

Tin spontaneously grows whiskers over time.  These can be 10 mm long.  In electronic equipment, a whisker can reach out and cause an electrical short.  The short can be permanent, transient (as the whisker melts), or destructive (as the whisker vaporizes and takes some of the surroundings with it).  Other metals, including zinc, can also grow whiskers.  See Nasa Goddard site.

This is a picture of my block of tin.  I bought is along with some zinc and bismuth (to make crystals).  No whiskers yet... The metal came in the US Mail.  It was a heavy box. For this purchase, they changed the advertising slogan from "If it fits, it ships", to "What the hell you got in here!?"