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Re: [Phys-l] water heating - recap

I wrote earlier:
I calculated the input power to produce this result as 91 watts into 176.3 g. water. The wattmeter was indicating 84 watts for this. Checking the heaters, I reada resistance of 195 ohms, and the input voltage 121 V.This should have provided a heating rate of 75 watts. This complete lack of agreement put a stop to the next phase...So much for the joys of H.S. experimental procedure.....
I finally twigged the problem, though I had not provided enough clues for you to easily guess what
it was. I noticed that the connecting wires for the heating resistors were discolored.
I coated the bare wires with epoxy, and tried again with distilled water.
This time the least squares straight line was 0.12028 deg per second into 150.0 gm water.
This provided a heating input estimate of 75.4 watts
The wattmeter indicated 73 watts and the Vsq/R amounted to 74 watts.
Much more the discepancy you might expect....
I had not accounted for the electrolytic heating before.
Ho hum....