[Havelock (OP)]

Hi) When I was a child we often placed a small parts of orange peel into a pools that left after the rain on a ground. These peels then starts floating in one direction like a small motorized boat and it was a rainbow trail left behind peel, just like film that left from gasoline/petrol on a water surface. Can you explain this somehow, please?)) Well, not about film itself, but about movement))) What is it and how does it work?))

[RD]

This example uses soap rather than oil (of orange) to alter surface tension ...

http://www.chaosscience.org.uk/pub/public_html//article.php?story=20031223132655581

[Havelock (OP)]

Oh, cool) Thank you! So it will happen with oil too? I'll do some experiments)

[LeeE]

I remember, as a child, seeing the same effect where a little bit of tree-sap of the right type and consistency would produce the same effect.  We'd put a little sap on the end of a small straight twig to make 'speedboats' and if we were lucky, they'd go in a straight line instead of around and around in circles.  They left the same sort of trail behind them.