[neilep (OP)]

During the early hours of the the night/morning I heard on the radio some people discussing the fact that someone had spilt tea over their computer !!..the question was asked as to whether there was sugar in the tea !!...why ?...does sugar exaggerate the reaction between liquids and electricity ?...or is just a load of BS ? there was not an answer given as the discussion quickly moved on to something else.


'Men are the same as women...just inside out !'  

[Donnah]

Sugar is sticky and a bugger to get out of a keyboard.

[tweener]

If you were talking about water, then yes, sugar would make it more conductive because it would provide ionization in the water that would conduct electricity.  However, tea would already have so many "imputities" that I doubt sugar would make much difference in the conductivity.  Regular tap water is a pretty good conductor, but really pure distilled water is a very good insulator.  Add a little salt (or sugar) to distilled water and it suddenly becomes a much better conductor.

And, sugar is a real bugger to get out of the keyboard.  So much so that I'd probably be in the market for a new keyboard just to avoid having to clean it out.

----
John - The Eternal Pessimist.

[neilep (OP)]

Well, cover me in feathers and call me a chicken !!!.. i did not expect there to be any truth in what I heard but thank you very much moderator sir......so there's truth in what I heard...and thanks for the tip regarding sugar in the keyboard.....I won't be stirring my morning coffee with two sugars with my keyboard any longer !![]


'Men are the same as women...just inside out !'  

[chris]

Are you sure that sugar would increase the conductivity of tea, John ?

Sugar (sucrose) - is not ionized in water, so I'd have thought that it would not affect electrical conductivity.

Chris



"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx

[cuso4]

I've heard somewhere that pure water actually don't conduct electricity well. H2O being a very very weak acid hardly dissociate in solution. The water which conducts electricity contains mineral ions which allow electrons to flow through.

Sucrose could be hydrolysed by water into glucose and fructose, couldn't it? It will just be a little slow. Or do you need sucrase to hydrolyse it?

Angel

[chris]

But glucose is similarly uncharged / unionised in water. The hydrolysis of sucrose to 2 molecules of glucose is achieved through the addition of a water molecule to the glycosidic bond between the 2.

I don't think a glucose, or sucrose solution for that matter, will conduct electricity any better than a solution of water alone.

Angel, you are quite right, pure water is a very poor conductor because it is hardly ionised. Try doing a bit of kitchen electrolysis and you'll find that very few bubbles of gas form on the electrodes in a solution of distilled water. Add some salt and it will go crazy !

Chris

"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx

[tweener]

I really don't know about sugar in the water being ionized.  If it is not ionized, it should not affect the conductivity.  However, a little sugar or honey in the water makes it heat faster in the microwave, at least that is my hypothesis.

***  Minutes later  ****

OK - to check this hypothesis and put this issue to scientific scrutiny....I did an experiment! [8D]

I took two clean cups and filled each half full with distilled water.  I put a spoonful of sugar in one of the cups.  Then I placed them both in the microwave for 1 minute.  In my experience with this microwave, a cup of tea will be lukewarm after one minute.  Using distilled water, I would expect the water to not be warm (though the crud on the inside of the microwave would be lukewarm[:p]).

*** 1 minute later ****

Both cups of water were luke warm. []

So, on the one hand the experiment failed, and I suspect there was some contamination involved.  Like the distilled water was the cheap stuff from Wal-Mart and was about two years old.  And the cups might have had a little soap scum from the dishwasher (they REALLY were clean though!).

On the other hand, I think I proved that the sugar did not make a big difference in the conductivity of the water, else the sweetened cup would have been warmer than the other.  Maybe, unless the contamination was bad enough that nothing would have mattered.

On the bright side, I added some tea, combined both waters, added another couple of minutes to the microwave and I am now sipping hot tea while admitting my poor scientific technique. []

----
John - The Eternal Pessimist.

[chris]

John,

a more accurate approach would be to take 2 carbon electrodes and a battery. electrolyse the 'pure' water for a given period of time and collect the volume of gas given off at each electrode.

Then repeat the experiment with the same volume of water but containing sugar. I predict that you will collect no more gas than in the first experiment.

Now add a spoonful of salt (which is fully dissociated into sodium and chloride ions in aqueous solution) and you'll see a huge increase in the volumes of gas produced...plus one of them will be chlorine so watch out !

Chris

"I never forget a face, but in your case I'll make an exception"
 - Groucho Marx

[gsmollin]

quote:Originally posted by neilep

During the early hours of the the night/morning I heard on the radio some people discussing the fact that someone had spilt tea over their computer !!..the question was asked as to whether there was sugar in the tea !!...why ?...does sugar exaggerate the reaction between liquids and electricity ?...or is just a load of BS ? there was not an answer given as the discussion quickly moved on to something else.


'Men are the same as women...just inside out !'  

I think the problem with the sugar is that it leaves a residue behind after the water evaporates. The sugar remains hydroscopic, and will stay sticky, and slightly conductive, for the remaining life of the equipment. Now tea does not contain phosphoric acid, like Coca-Cola, so it wont eat your equipment up like that will. It is a moderate problem for the electrical circuits, when dried up. It is a real hazard when wet. Just about any liquid is a real hazard, when wet, to your electrical equipment. My son has a scrap G-Force 4 card that got wet. The 3.3 V Vdd supply stripped the gold off of the card finger and the card failed. Luckily, the AGP slot connector did not get wet, so the whole motherboard did not fail too. That water was distilled, with an anti-corrosion inhibitor, that leaked out of a water-cooling hose.

[neilep (OP)]

Forgive my ignorance gsmollin, but would something like WD40 help  ?

'Men are the same as women...just inside out !'  

[gsmollin]

WD-40 is an oil with some solvents mixed in. Great stuff. I'm not sure how to use it here, though. It won't mix with water. If you are asking how to clean the sugar residue out of the computer, I'm not sure is my answer. I would have to experiment with it myself, or ask for expert help.

If I had to go it alone, I would try both a 50% water-alcohol mixture, or 100% distilled water (but not both) on some scrap items as a process-qualification. Then I would use the most effective solvent. Dry at room temp, then bake in an 85 degree C oven for 8 hours.

[qpan]

quote:Originally posted by tweener

I really don't know about sugar in the water being ionized.  If it is not ionized, it should not affect the conductivity.  However, a little sugar or honey in the water makes it heat faster in the microwave, at least that is my hypothesis.

Surely adding impurities to water would not affect the rate of heating as thermal conductivity is totally different to electrical conductivity?

In electrical conductance, the ions move, allowing for a a flow of charge. In thermal conductance, the mechanisms are totally different, so even if the microwave experiment had worked, it wouldn't have proved anything about water's electrical conductance when impurities (whether ionised or not) are added!

"I have great faith in fools; self-confidence my friends call it."
-Edgar Allan Poe

[tweener]

Qpan - Adding impurities is what makes the microwave able to heat the water because it heats by inducing electrical currents in the water (or whatever is in the oven).  So, you want to enhance the eletrical conductivity.  That's why the plate doesn't get hot.  Or distilled water if it really is pure.

And Chris, I don't have all that fancy equipment in my kitchen.  Besides, I wanted the cup of tea, not chlorine!

WD-40 is great stuff, but it definitely wreaks havoc on electronics (some experience involved here), so it probably wouldn't be the most appropriate thing to spray on your motherboard.

And, gsmollin, why does your son have a water cooling hose in his computer?  Is he overclocking?

----
John - The Eternal Pessimist.

[gsmollin]

Oh yes. He's got all the hottest (literally) CPU and memory and motherboard. I can't remember all of it, but the last addons were twin WD Raptor drives for Raid 0 setup.

OBTW, the heating issues with microwaves and food are very complex. It is not so simple as just creating currents in the food, as in induction heating. The dielectric properties of all matter change radically with frequency. The frequency chosen for the microwave oven (which I can't remember) is very close to a resonance with the water molecule, making water absorb microwaves very efficiently. Adding sugar to the water wouldn't improve it. Dry sugar is pretty transparent to microwaves, and stays cool in the oven.

[neilep (OP)]

gsmollin....with regards to the dry sugar in microwaves....would that also apply to anything that is moistureless ?

'Men are the same as women...just inside out !'  

[tweener]

quote:Originally posted by gsmollin

Oh yes. He's got all the hottest (literally) CPU and memory and motherboard. I can't remember all of it, but the last addons were twin WD Raptor drives for Raid 0 setup.

OBTW, the heating issues with microwaves and food are very complex. It is not so simple as just creating currents in the food, as in induction heating. The dielectric properties of all matter change radically with frequency. The frequency chosen for the microwave oven (which I can't remember) is very close to a resonance with the water molecule, making water absorb microwaves very efficiently. Adding sugar to the water wouldn't improve it. Dry sugar is pretty transparent to microwaves, and stays cool in the oven.

The frequency that microwave ovens use is somewhere around 2.4 GHz.  And yes the heating mechanism is very complex to try and analyze.  However, liquid water does not resonate very well at any frequency because the molecules are all sort of stuck together.  This makes the absorption spectra very complex.  The molecular absorption for water at 2.4 GHz is due to the rotation of the molecule induced by the dipole moment trying to line up with the (rapidly changing) magnetic field.  

Any time a time varying eletromagnetic field impinges on a conductive material, currents will be induced.  This is due to the free electrons (ions) being induced to move in the electric field.  The dielectric constant varies with frequency, but at 2.4 GHz an ionized glass of water is still a pretty good conductor, though certainly not great.  The losses due to the current flow are high, and show up as heat in the food.  

I don't know which of these mechanisms contributes more heat, but I'm willing to bet the induced current is larger.

Because the electric field induced charge tends to intensify near sharp corners, the food heats more at the edges than in the center.  That is why microwave plastic dishes have a rounded bottom - so they don't overdo the food on the bottom.  The top still does, but can't really be helped because there is no way to round the edge of the food.


----
John - The Eternal Pessimist.

[neilep (OP)]

quote:
Because the electric field induced charge tends to intensify near sharp corners, the food heats more at the edges than in the center.  That is why microwave plastic dishes have a rounded bottom - so they don't overdo the food on the bottom.  The top still does, but can't really be helped because there is no way to round the edge of the food.


----
John - The Eternal Pessimist.

John, that must be why I have seen some recipes where they say to put silver foil on the edges....for instance if you're heating up a chicken , I've sometimes seen that small pieces of foil are used on the wings, or the tip of the legs......so, it's obviously alright to do that eh ?

'Men are the same as women...just inside out !'  

[tweener]

I've heard that but never tried it.  I know if you get metal close to the sides, you can get some pretty strong sparks, maybe strong enough to knock a hole in the side of the oven (a little experience here too[]).

----
John - The Eternal Pessimist.

[Ylide]

http://www.angelfire.com/electronic/cwillis/microwave.html

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