OK, then you were actually measuring a change in density instead of
weight. That would likely have been an decrease in volume then instead
of a decrease in weight.
This could be cause by any of the following:
1. scale accuracy
2. scale repeatability
3. temperature difference in the liquids at time of measurment.
4. pipette accuracy/repeatibility
5. actual density reduction
Actual density reduction could be due to temperature variation or a
change in the structure in the water. For instance if water
crystallizes when freezing, the density will drop about 10%.
Marshall
On 2/28/2011 5:37 PM, Neville Munn wrote:
Hope this doesn't come thru twice, had to cut.
Yep, sure.
2 Different solutions used: (a) 19 days old @ 12.1uS/006-7ppm, (b) 3
days old @ 18.5uS/009-010ppm.
Step 1: Ensure digital scale was zero'd and reading in grams. Praps I
could have used 'ct' or 'gs' {which I assume is 'grain'} or 'dwt'
{don't know what that is}
Step 2: Weigh empty 30ml plastic medicine cup.
Step 3: Syringe 5cc/ml plain DW into cup...weigh that, then subtracted
cup weight from DW.
Step 4: Empty and dry cup thoroughly.
Step 5: Syringe 5cc/ml EIS into cup...weight that, then subtracted cup
weight from EIS.
Step 6: Subtact this result from the other.
N.
------------------------------------------------------------------------
Date: Mon, 28 Feb 2011 12:52:56 -0500
From: [email protected]
To: [email protected]
CC: [email protected]
Subject: Re: CS>Wet weight?
Can you elaborate a bit more on your procedure?
Marshall
