From: RoyMayeda@aol.com
Date: Fri Dec 07 2001 - 06:16:07 PST
From: RoyMayeda@aol.com Message-ID: <12f.8d6543d.29422927@aol.com> Date: Fri, 7 Dec 2001 09:16:07 EST Subject: Re: bio lab
Geoff,
Did the instructor who made the agar remember to put the phenolphthalein or
other acid-base indicator (high pH range change indicator) into the agar
before pouring the blocks? There is no color change with the agar and NaOH,
but if you have an indicator present, it'll show the distance into the block
that the NaOH has diffused. (I've not done that one, but some other
instructors said it took quite a while to get significant penetration. If
they got NO change, then the indicator must have been left out.)
Roy Mayeda
Valley HS, Sacramento
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