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RE: If an oxygen molecule...
Charley Bay wrote:
> Additional gas is forced into the water through
> pressure.
and
> There are pockets of air in almost all pipes that
> result from bacterial and chemical reaction, or
> from turbidity in the system (stop and go flow
> traffic, pressure changes, turbidity around bends
> and diameter steps.) These pockets are forced
> into the water at higher pressure, and "de-gass"
> at lower pressure. If you're a drop of water en
> route to a faucet, you really have a violent ride
> (if you can keep yourself together at all ;-).
>
> More practically, plumbers know that it's always the
> hot water pipes that freeze and bust in the winter,
> because they came from the hot water heater and
> cooled, they have more dissolved gas, so it takes
> a smaller energy change to freeze the pipe (more
> gas, less water, gas has a lower specific heat
> value for a temperature change.)
I still don't understand where the gasses come from. Possibly, a small
amount may be generated by some chemical reaction after the water enters
the pipes. I would like to believe there are VERY limited spontaneous
chemical reactions in the water one drinks.
As to the gas pockets in the lines, the times we are doing the water
changes are typically during the high use/low pressure period, which should
yield lower dissolved gasses. Also, there is a "material (mass) balance"
thing that controls here. Assuming significant gasses are absorbed during
times of low use/high pressure, on average, what comes out of the faucet
cannot be more that what enters the distribution system. In other words,
while a small increase may occur at some time, a proportional decrease must
occur at others.
Does this make sense to anyone else, or am I past left and out in the
parking lot somewhere?
As to the hot/cold water freezing issue, here is a link to an interesting
article on the subject;
http://www.urbanlegends.com/science/hot_water_freezes_faster.html
Douglas Guynn, praying for rain, but hoping it holds off until Saturday
night so I can finish the yard work...