Comment by JKCalhoun | Hacker News Reader

Comment by JKCalhoun | Hacker News Reader

As a "mad scientist" when I was perhaps eleven or so, I created a carbon arc by cutting the end off an electrical zip-cord extension cord, stripping the insulation off the two wires (lol, yeah, no ground wire) and wrapping the bare copper ends around a pair of carbon rods pulled from D-cell batteries.

I held down each carbon rods by attaching it to a brick. Move the bricks together to touch the rods together to get a spark and an orange growl, and then draw them apart into an intensely bright white-hit light.

Insane. Yes, I tripped the circuit breaker (thankfully not fuses in that place) repeatedly.

Decided to make a saltwater rheostat to control the current. This time a square glass casserole dish with salt water was the tank. One of the mains wires was cut and enough insulation stripped to wrap around two rocks placed in the brine. Move the rocks closer, more current, move the rocks apart, less current.

Holy hell, that was something. When the arc got to lighting up the basement I looked around to the rheostat to see it arcing under water as it bubbled (as another mentioned, yeah, probably chlorine gas). When the insulation on the zip cord soon started to smoke I decided the experiment was over and jerked the cord to pull it out of the outlet. This quick yank also sent the glass casserole dish crashing to the ground....

Ahhh ... if only YouTube were around then. I might have tried to do it more safely. https://youtu.be/VTzKIs19eZE

Instead I got the idea from the book "700 Science Experiments for Everyone" (p. 185): https://archive.org/details/isbn_9780385052757/page/184/mode...

Love hearing stories like this about unfiltered, unfettered (and slightly insane) childhood play. Parents today don't even let their kids walk 2 blocks to school unsupervised, lest something terrible happen.

I wouldn't let me do that now, ha ha. I could have burned the house down. (I did burn my friend's eyebrows off, but that's another story...)

The danger in that story is pretty off the charts. That could have _easily_ led to death, like maybe 1/100? That's something parents _should_ stop. It could have been redirected to safer versions, you can have a lot of fun with lower voltage DC, or at the very least safer setups.

Electrocution with mains is... actually not that common if you take care to not let the current pass through you.

I'd be more concerned about the intense UV that an arc emits ("welder's eye").

I was once playing with mains (220V) and got distracted on the phone with a friend. I literally took with each hand one cable (they were crocodile terminals) I just could not let go, the current makes impossible to let go. I reacted like 5 to 10 seconds later, by letting me fall backwards, which disconnected the leads from the plug. I was 15 or 16…

I should have gone to the hospital, but I didn’t.

So, I do bot say it is not dangerous, but it is not like it will kill you in 1ms.

I once shorted 380V with my little finger (testing industrial electric motors for overheating). It was like someone hitting the finger with a sledgehammer.

Oh I did not mention it, but the hands kept hurting one or two weeks after that. Really not funny. But 380v is another level of danger, energy goes ^2 with voltage!

Well it was really just the pinkie (and the arm a little bit), but it felt more like a kinetic hit then a electric-shock, pretty terrifying, the pain lasted for like a week (damaged bone marrow?)

The most I ever got shocked with was 560Vdc @ 10mA I know it was 10mA because it popped the safety breaker on the lab power supply. I was testing a clamp circuit for a high power solid state RF matching network. I had been so careful the whole time using only one hand, but I got complacent for one second and BOOM, hand-torso-hand circuit.

It felt like I got kicked in the chest. Was sore for a few days after.

So lucky I was using the lab supply with a good breaker.

Would have been a bad time to find out you had a heart condition. Grabbing with both hands (and being distracted) is indeed very dangerous, which is why the comment you replied to mentioned taking care. Many electricians will do small tasks without cutting off the power and it’s entirely possible to do things reasonably safely if you take some basic precautions.

I thought is needless to say that no once more in my life was distracted while working with anything above 12V... I've much more respect now.

> Parents today don't even let their kids walk 2 blocks to school unsupervised, lest something terrible happen.

Though weirdly enough, they mostly aren't even worried about the real danger, cars, but about some imagined but much less likely scenarios.

I am so used to type-G plugs that I didn't initially realize why you'd be concerned about blowing a fuse.

When I was about that age I also shocked myself pretty bad a couple of times, once from replacing the fuse in a plug and pressing the plug into a socket using my palm without putting the rear cover back on. Another time touching two spoons I'd put into the live/neutral holes after using one of them in the earth hole to bypass the safety gates. (I assume I inserted the live one last) I remember finding it interesting how neither seemed to shock me individually, then touched both and leapt back across the room.

Surprised I didn't die from that second one. I still viscerally remember what 50hz sounds/feels like.

220/240V shocks hurt like all hell, and it kind of "reverberates" in your affected limb long after. The auditory experience is also quite strange. You can hear the 50hz, but it's more like an "understanding" of the sound than actually hearing it. Very weird.

If you grabbed the two spoons with both hands, you probably would have had a worse outcome. One hand touching both terminals hurts, but will likely not kill. When that current comes close to your heart you'll have trouble.

The fact that neither of them didn't shock you individually is likely because you were insulated from the ground. You had shoes or clothing on or something. If you had skin touching the ground, bad news again. I had a fridge that had broken down motor insulation or something, and it kept tripping the earth leakage. I had no money to replace it, so I cut the earth wire in the plug. Problem solved. Just made a note to not open the fridge while barefoot. Eventually I got round to getting rid of it thankfully.

The common advice when working on something dodgy is to put one hand in your pocket. That way a shock will give you ample warning to back off before killing you. Unless it's DC - that stuff scares me. My old solar installation had a 550VOC DC potential, and I stayed the fuck away from that. I have 0 problems working on domestic AC, but not solar DC!

220 scares me for exactly that reason. I've been shocked by US 110 pretty good a couple of times but the pain has never really lingered beyond a couple seconds after the initial shock. I certainly didn't hear anything.

While the plugs in the US not being shock-proof is certainly not great, I think it's a lot less of a danger than it would be in a 220 country.

YouTube wasn't around back then but luckily the "mad scientist" spirit still lives on: https://m.youtube.com/watch?v=co6SUTVGqOs (en subtitles available)

I remember getting that book from the library and reading it cover to cover. I never really tried to do any of the experiments, though, but it was definitely my favorite science book as a kid because it wasn’t full of safe and boring experiments

That's hilariously dangerous. I will be getting my son that book.

> bubbled (as another mentioned, yeah, probably chlorine gas)

Suddenly I am reminded of my A-level Physics project, where I tested the relationship between salinity and conductivity with some graphite rods in a beaker of water - has to move to a chemistry lab and use their fume hoods after the first day of testing :D

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