water floats on oil?

[Bernard Heymann]

In article <2kk885$h7g at dingo.cc.uq.oz.au>, rogerM at qimr.edu.au (Roger
Mitchell) wrote:

> This is just an observation I have noticed recently when doing some PCR reactions. After setting up the reactions I place the tubes opened into the PCR 
>  machine (Perkin Elmer 480) and add two drops of mineral oil (Sigma) by a
>  sterile pasteur pipette, close the lids, then immediately begin the relevant
>  file for the reactions. Later I have checked the machine to ensure all is
>  going well,(you never can tell when FATE strikes you down) and noticed condensation inside the lid of some of the tubes, though not all. 

As a matter of routine, we give the tubes a quick spin in a microfuge after
adding the oil to ensure everything to be in its proper place. This avoids
having to ask the questions you have :-)

-- 
Bernard Heymann
bheymann at bragg.bio.purdue.edu