Before reading any further -- DO NOT TRY ANYTHING YOU READ HERE YOURSELF. Not only will you void your warranty, but you could cause harm to you, to others, and most definitely to your equipment. Just because we happened to get one result and were able to pull this off safely does not mean that you can expect the same. If you want to be stupid, do it on your own time, but don't claim you got the idea here.
One of the most interesting things I've gotten to do so far this year is consult for the water spot for a recent ad campaign.
Warren, our chief photo expert, (not his official title) was working with our advertising agency to coordinate the filming of this spot. He called me one afternoon some months back and said "We've got this idea. We're going to drop a running ThinkPad into a NASA test tank and see what happens. Er...except...we don't know what is going to happen. What could happen?" What a GREAT question. He instantly had my attention. While I talk about spill tests all of the time, this was taking it to the extreme. I never had thought about what would happen if someone just decided to dunk their machine. He and I began to talk through the possibilities. We knew the system was going to be toast. (Yes, that is a technical term). The only question was how long it was going to last. I wish I had remembered my guess as to how long it would keep running, because it would have been interesting to compare my guess against reality later. Knowing that the system was going to die, the team also had some safety concerns. After all, they were dunking an electrical appliance into water. This is something that even a 5 year-old knows is a badidea. The worst case of what could have happened is that the Lithium-Ion battery itself could have been severely damaged and that water would get inside when the system was submerged. Any chemist out there knows that Lithium + Water = a reaction. However, the likelihood of this reaction occurring was pretty low for several reasons. The first is that the lithium in standard batteries is far from pure. It has many other chemicals mixed in which made it unlikely that it would react with water. The second reason is that unless the battery pack were obviously cracked or purposely damaged, it is sealed and water would not have gotten inside anyway. The next concern was possible electrocution of the divers. (The space suit was likely to keep the astronaut safe no matter what happened.) First, we were not going to immerse a plugged in system. That probably would have caused major problems. So with the idea that the system would be self-contained and running on battery power, Warren and I talked what kind of damage the voltages inside a running system could pose. Most of the system components like the memory or hard disk drive run on less than 10 volts. As anyone who has put a 9 volt battery on their tongue can attest, while you can feel a tingle, this is hardly life threatening. One possible concern was the display voltage regulator. In order to power the display and light the florescent tubes, the voltage is ramped up by a special inverter card in the display. However, even though this voltage is higher than the rest of the system, it really wouldn't be enough. There aren't enough amps of electricity delivered at any given time by a properly discharging battery and the current itself wouldn't be concentrated on a wire, but rather radiated in all directions inside the tank. The battery itself has a safety circuit that detects all sorts of conditions like rapid discharging or cell discharging imbalance (and a whole host of other issues) and preventively shuts down in case these fault conditions happen. One other thing. Water itself is actually a relatively poor conductor of electricity. We briefly flirted around about whether dropping the system into salt water would have changed anything. I don't believe it would have. In any case, the NASA tank is a fresh water tank, so it really was a moot point. As a final chuckle, we laughed about the team's worrying about what would happen. They talked about dropping a system into a bathtub the night before to try it out, but no one wanted to stick their hand in the tub. They went back and forth saying You do it. No, YOU do it. I'm not sure that they ever did the test, but just went ahead and showed up at NASA and dropped the system into the tank. The result is what you see here. Oh, and the system lasted for 3 seconds. Longer than I think I would have expected it to.