Just curious about a peculiar observation

brett brett at BORCIM.WUSTL.EDU
Fri May 23 19:31:20 EST 1997

>If you're a molecular biologist, there's a good chance you've experienced
>this peculiar phenomenon before: you take a 1.5 mL eppedorf tube containing
>about 100uL of solution (any solution, DNA, DTT, etc...) from a -20 freezer
>before it has frozen, the solution is clearly in liquid phase, then you
>flick the tube or you gently shake it, and as if magic by magic, the
>solution quickly freezes within a fraction of a second, making you wait 5
>minutes for the now frozen tube to thaw.
>Nobody I've met so far can explain it. Can any of you?

It was already cold enough to be frozen, it just hadn't crystallized. Somehow
flicking the tube disturbs the solution enough to begin crystalization and
wham-o. you now have a frozen tube. happens all the time, but especially with
DTT and ampicillin.
Brett Lindenbach
Dept Molecular Microbiology
Washington University School of Medicine
St Louis, MO

"One thousand miles an hour, I'm just like anyone.
I want to feel the road of tar beneath the wheel
named extinction" - Pixies

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