Topic: Water temperature

[choppert]

Hello,

Daft basic chemistry question alert!

I've just knocked a spreadsheet together which will calculate how much of a certain temperature of water to add to another to get to 18 or 20 degrees (ie if my tap water is 13C I want to make 750ml of 18C water how much hot water do I need to add to get my 750?)

So here's the question....

If I mixed 1 litre of 100C water with 1 litre of 50C water will I have 2 litres of 75C water?

Is it that simple?  

I experimented and it appears to be.

(I'm not that concerned about how long it will remain at that temperature - for now)

Thanks,


Chops

[Francois]

Weird... I never even got thinking about that!
In my mind, that sounds OK (it's just an average).

Thing is that the volumes of liquid will have a definite effect on the results. Small volumes of very warm or cold liquid will have a smaller effect on the larger one... so I think that averaging per volume unit would be a better bet.

So, a 50+50 dilution would not me the equivalent of a 1+1 dilution...

This is a thermal transfer thing...

[DaveMiller]

Yes, near enough.

[Francois]

I thought of it when I was awaken this morning by construction workers banging on a big dumpster...
I think averaging would be the simplest thing to do.

Else, it would mean getting into thermodynamics, insulation capabilities and boundary layers... not worth the trouble...

[f6point3]

I tend to rely on ice cubes and the microwave for thermal controls.    The tap water here in South Texas is generally about 80 F year-round, with the exception of February.  Too much ice, into the micro you go for a few seconds.  And so on.  I use a meat-thermometer for my thermal read-out.  Dynamic enough fer ya?