The first assumption is correct; that is, balance three first, then the
other two. Along this line of argument, in a 24 hole rotor, 7 tubes can
be balanced by balancing the first three then the next four. 13 tubes
by 3x3 then 2x2, etc. In the 5 tube in 12 hole rotor case where the
tubes are balanced 3 then 2, the rotor can indeed be divided into two
equal halves- it's just not easily visualized.
Hope this helps.
On 9 Oct 1996, John Dixon
> Date: 9 Oct 1996 15:38:58 GMT
> From: John Dixon <jpcd0 at mole.bio.cam.ac.uk>
> To: methods at net.bio.net> Subject: 5 tube balancing argument
>> At the risk of starting a bandwidth hungry inconsequential argument
> (judging by the amount of time spent in our lab jibbering about this), I
> would like to ask a simple question:-
>> Some one here was doing 5 minipreps (equal volume) and was loading a 12
> hole microcentrifuge, when he found that the balance tubes had been
> cleared away. He was about to fill another sixth tube to balance 3
> opposite 3, when I said that you can balance five anyway. This started a
> massive debate, which has now come down to three positions.
>> I reckoned that if you put three tubes in, in a triangle ie in holes 1,5,9
> these are balanced. Then you can balance the two others opposite each
> other in holes 2 and 8.
>> One guy maintains that this is not balanced at all, on the grounds that
> you can split the fuge into two halves where one half has two tubes and
> the other has three, therefore it must be unbalanced. I am not convinced.
>> Then another guy said that he balances five by putting them in as near a
> pentagonal position as he can ie 1, 3, 5, 8, 10. I dont think this is OK
> because you cannot remove a balanced pair to leave a balanced three,
> although I doubt it does much harm.
>> Are there any centrifuge balancing experts out there?
>> Apologies for innapropriate use of the newsgroup, but maybe some of us are
> trashing our fuges and more importantly several pints are resting on this!
> John Dixon Lab 44 (1223) 334131
> Wellcome/CRC Institute Fax 44 (1223) 334134
> Department of Genetics
> Cambridge University
> United Kingdom e-m: jpcd0 at mole.bio.cam.ac.uk>>
"You know, it sure would be amino world without RNA"
Center for the Molecular Biology of RNA
Department of MCD Biology
University of California
Santa Cruz, CA 95064
e-mail: howe at darwin.ucsc.eduhttp://www-biology.ucsc.edu/people/areslab/ken.html