Originally Posted By: Hammehead
You can compare surface tension between oils, by droppin it in water at 25C and see the one that beads up faster and remains most floating is the winner.
Yeh, right.
And you'll be quoting "bead-up-speed" and "floatingness" to how many decimal places of what?
I've seen behaviour of an oil droplet suggested as a measure of oil degradation, and tried to read up on it quite a while ago. IIRC the idea is that polar compounds are formed during degredation which lower the surface tension via their greater affinity with water. IIRC again
(a) It doesn't work very well with modernish oils because they can contain polar molecules when fresh.
(b) Quantifying it by measuring surface tension is the mother of all metric nightmares.
(c) Surface tension measurements form the basis of no operational industrial oil quality tests, at all.
But maybe I missed something, or there's been a breakthrough.