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Name: James
Status: student
Grade: 6-8
Location: PA 
Country: N/A
Date: 1/30/2005


Question:
Can snow or ice conduct electricity? If I put snow or ice on a micro chip, will it short circuit, or hurt me?


Replies:
On a microchip, it probably will not hurt you unless you are touching it yourself. However, because they are much colder than an operating microchip, and because they will quickly begin to melt and put water on the microchip, chances are you will quickly destroy the chip. (The case may or may not remain intact, but the chip will still be ruined)

Ryan Belscapmer


** I DO NOT recommend putting any water, ice, snow on or in your PC or any other electrical circuit for the purposes of cooling it down or for any other reason. **

James,

Liquids / solids conduct based on one simple idea which I may be oversimplifying here: They need CHARGE CARRIERs. If you were to place snow or ice on the uProcessor it would more than likely immediately melt on the IC / uProcessor. Also, the runoff water will more than likely STILL interfere with the operation of the IC.

Will it SHORT CIRCUIT. Well, of course it will not SHORT circuit. But it really kind of depends on how many other IC's are attached to this IC. Water is NOT an inert gas that has zero electrical properties. If it were to dissolve some solids on the PCB after the snow / ice melted the conductivity could very well increase acting as a partial short circuit to other pins.

Personally, I have dunked an entire PCB filled with IC's in a small bath of water to keep it cool. But that is because I knew that the IC's were pretty tough (electrically) and that there was a lot of water used. So if there were any dissolved solids on the PCB they would be so rapidly DILUTED that there would be very very little conduction in the water.

Will it hurt you? No one can ever make any absolute promises that you will not get hurt from dumping water on an electrical circuit...so I will error on the side of caution and say that if do not know enough about the circuit (IC) and DO put ICE / water on it...chances are you could get shocked if you were to touch it the wrong way.

a.) Example of NO ELECTRICAL SHOCK HAZARD would be a simple 5 volt circuit with a 555 timer w/ NO Inductors / coils / transformers present.

b.) Example of an ELECTRICAL SHOCK HAZARD would be a SEEMINGLY harmless circuit that contains a triac that may be used to switch off and on a 120Vac voltage source. If you were to put ice / water on that the higher voltage would cause greater current to flow. Furthermore, the greater current may be responsible for the metal finish eroding from the PCB surface and going into solution. This presence of more FREE IONS caused by metal erosion will further increase the conductivity of the water causing the 'situation' to cascade out of control until either a fuse blows or a circuit trace blows open...or even worse.

The above two examples are not just supposition. THEY ARE FACT. I have experienced both and know them to be true. "SO DO NOT TRY THIS AT HOME". ;)

Hope this was helpful.

Darin Wagner


Extremely pure water is a poor conductor of electricity, as is extremely pure ice. However, it is extremely difficult to produce sufficiently pure water. For example, glass is sufficiently soluble to cause contamination. I would not recommend putting water on a micro chip, it is quite likely to short out unless the circuit has been over-coated with a protective coating. It is not likely to harm you because the electrical power is low in most micro chips -- but it is not going to do the chip any good.

Vince Calder


Not my field, my layman's opinion. Snow and ice are just other forms of water, so would you put water on your chip? Then, consider the snow, or ice changing to water under the conditions. This opens the thought about vacuums, or climate controlled safe rooms. So, I would guess the answer depends on under what conditions.

James Przewoznik


The microchip will not hurt you, but putting any form of water on anything that uses any kind of electricity requires the supervision of a knowledgeable adult.

If the microchip and everything in the vicinity (everything that any melted ice might possibly touch) is powered by a low-voltage, low-current supply (for example, three ordinary AA batteries makes 4.5 volts, which many microchips will be happy with) then you can take relatively simple precautions to remain safe. The voltage from three AA batteries cannot hurt you, but even such a weak supply can produce enough heat to burn your finger, start a fire, or melt or vaporize something that was safe as a solid but is not safe as a liquid or a gas.

If the snow or ice is uncontaminated (for example, ice made from distilled water, and not touched by anything that might add impurities, such as your finger) it will be a very poor conductor of electricity, and will not short out the microchip. The microchip and circuit board must also be very clean (washed with alcohol, for example) or any water that melts out of the snow or ice may pick up enough impurities from the surface of the chip or the circuit board to become conductive.

Tim Mooney


James-

That is an iffy, on-the edge situation, with lots of little things to say about it. You were not very specific as to what kind electronic device you might see doused with snow.

Snow or ice usually have melted water on the surface, or could get some easily. Especially because most microchips make some heat. Water does conduct, and definitely can make short-circuits. If there is high voltage, yes, it could hurt you. Snow and TV's, for example, are a really bad idea.

Ice itself does not conduct very much. Especially below about -10 degrees C. A desk computer that was pre-chilled and filled with very cold dry snow would probably work OK until the heat it normally makes started melting the ice. And continue OK for a little while even then. Only the power-supply box would have dangerous high voltages in it (120 volts AC), although you could get a nasty bite from grabbing a wet 12 v wire and a wet ground (0 v) metal part.

Some of the lowest-power microchips could live normally in a solid block of ice at -10 degrees C. A digital quartz wrist-watch, for example. The LCD display might have a problem showing clearly, but the clock chip behind it would be doing its job. I think the battery would be OK, too.

Most of the chips I would call "micro-chips" only use 3v or 5v, not normally enough voltage to hurt you. Try touching the terminals of a 9v battery to your tongue. Carefully, because it is strong; it almost bites. You can imagine that 5v is less, and your skin is blocks electricity more than your tongue even when it is wet skin.

But power transistors and power-amplifier chips, say in TV's or maybe in audio power amps, look a bit like micro-chips, and they often handle hundreds of volts. They can be plenty dangerous. All glass-tube TV's are dangerous. Battery-powered electronics usually are not, unless they are TV's.. There are many low-power digital microchips that couldn't hurt you or even themselves by being shorted, but they might be unable to work properly until the short is gone.

Corrosion can kill your electronics. Sometimes when you get water on a circuit-board with micro-chips, it wicks into hidden places and stays there a long time, and while the power is on, voltage + water will power-corrode the printed wires and IC pins, and then later even if the water is gone the corrosion makes short circuits which keep on interfering with the whole thing. It could work again if shorting-trails of corrosion were removed, or prevented from forming.

If I had a computer or Game-Boy that got snow into it, I would treat it the same as if it had water squirted into it. I would turn it off right away and take out the batteries, open it up with a screwdriver soon and dab out the excess water with towels. Then later do a big job of LIGHTLY scrubbing the circuit-board with 70% rubbing alcohol and an old toothbrush, maybe rinse it with 90% rubbing alcohol, then dry it with towel, then with a hair-drier an arm's length away. Then put it back together, of course. If the electronic board did not have visible corrosion-crust anywhere yet, there is a fine chance it will still work.

I wonder what stories an electric-company linesman could tell us about downed power lines in snow. That sounds very dangerous.

Jim Swenson


Snow and ice are pretty good insulators. Neither one is as good as conventional insulators such as glass or plastic.

Snow or ice should not have an effect on a microchip. Of course, if some of the snow melts into water, the water will conduct electricity much better.

I do not know why you would put snow or ice on a microchip. If you want to use a homemade integrated circuit in a machine like a snowmobile, it will pose no problem. Microchips are sealed against water.

Bob Erck



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