How To Stick To Anything

By Tuesday, March 30, 2010 , , , , 0

I wrote in an earlier posting about Professor Brian Cox’s BBC TV series ‘Wonders of The Solar System’, well the BBC have started another great series called ‘Invisible Worlds’. It is presented by Richard Hammond (Top Gear presenter, amongst other things).

You can watch tonight’s show (and earlier episodes) on the BBC iPlayer. One of the shows items really caught my interest – geckos (or lizards) – how do they stick to anything? How can the support up to ten times their own mass? You have probably guessed …. it is by using ideas taught in the IB Chemistry subject guide!

The gecko can stick to virtually anything. But how? Well, each toe of the gecko has a dozen or so ridges. Each ridge consists of millions of tiny hair like structures that branch and branch and branch (and branch and branch and branch …..) giving the geckos feet a HUGE surface area.

The final branching of this tiny hair like structure is around 0.2 micrometers long, which doesn’t sound much but it is just below the wavelength of visible light! And that is it! But what about the Chemistry? Well, the larger the surface area the larger the van der Waal’s force. In this case the surface area (and hence the van der Waal’s force) is so large the gecko can stick to anything it wants!

Which came first though, the gecko or the IB Chemistry subject guide? 😉

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