I’ll get back to Rumford and the story of heat shortly, but having been distracted by the wonderful Fibonacci clock, I find myself even more distracted by the beautiful structures that water droplets can form themselves into when trapped inside larger oil drops. The Physical Review Letters paper by Jan Guzowski and Piotr Garstecki is not out yet, but above (left) are some of the pre-release pictures for seven water droplets inside one oil drop. Staggeringly, some form chains. Who said there was nothing new under the Sun?
The interesting part about this is that it was achieved without adding detergent, which is usually needed to forma surface coating that keeps the droplets apart and prevents them from coalescing. Perhaps the fact that the oil droplets themselves are suspended in another (immiscible) oil has something to do with it.
In a related story (at least, I think it’s related) scientists in France and The Netherlands have been firing lasers at millimeter-sized water drops. The side that the laser hits boils and the drops recoil away (see right-hand picture above). This way of manipulating droplets may have future applications in lithography, but to me both this application and the suggested applications of aligned water droplets in drug delivery smack of post hoc rationalization. My bet is that the scientists simply did their first experiments for fun – which is just as it should be.
Incidentally, if you want a good novel about scientists doing experiments for fun, try Thorne Smith’s Night Life of the Gods. Not to everyone’s taste, but I find it hilarious.