Re: [Killietalk] TDS vs Conductivity

[LeeH920226 at aol_com]

In a message dated 2/2/06 3:30:15 PM, bjc3 at centurytel_net writes:
<<  some substances dissolved in water would have colligative properties and affect such things as osmotic pressure without being measured by a conductivity (i.e. TDS) meter, which is what I think Lee is getting at. >>
Of course. Some every day examples of the depression of freezing point (another colligative property) are sodium chloride and calcium chloride deicers (ionic) and methanol and ethylene glycol antifreeze (nonionic). The other every day example of a colligative property is the elevation of the boiling point observed in boiling down of maple sap to maple syrup. The boiling point at the syrup stage is 218 degrees Fahrenheit, compared with 212 degrees for pure water. It is now almost time to collect my maple sap and observe this phenomenon once again. It has been so warm this January that I thought the maples would be early, but nope, nothing is flowing yet. Must be related to the hours of daylight as well as the temperature.     Now the obligatory referral to killifish. I just collected eggs from a group of Austrolebias alexandri that we collected in July 2004. They are surprisingly longâlived if kept cool.
Lee HarperMedia, PA
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