I did a similarly stupid thing one day. While repairing a clock for a display on a trade show I hooked the ground crocodile clamp of my scope to what I thought was the ground but which in fact was V- of the DC supply voltage of the neon light installation that was use to drive the display. I had a blind spot in the middle of my eyes for many days after that (and took out a fairly large chunk of the mains supply for the Eastern district of Amsterdam). The crocodile clamp totally disappeared, the scope, miraculously survived and wasn't even out of spec.
Every time I use a crocodile clamp to hook it on to something I think back to that moment when the clamp makes contact and some part of me expects it to happen again.
Yeao! I own a couple of high-voltage differential probes for this very purpose. Even though most single-ended scope probes are rated to 300V Cat II, I won't go anywhere near main's power with them.
"I bought some fuming nitric acid on eBay and spilled it on the carpet. Dad was pissed."
"I fused two screwdrivers together with a photoflash capacitor. Sears refused to give me a refund."
"I accidentally made chloramine gas and experienced short-term breathing difficulties."
"Yeah, well, I shorted out a nuclear submarine battery."
Well, I learned a valuable lesson that day; even relatively harmless camera flash capacitors can pack quite a charge days after a battery's been removed!
The giant spark made me jump back and fall over my chair, and my pliers still have two nice molten burn marks where it touched the contacts. I'm just glad the pliers had rubber handles!
I'm much more cautious around capacitors these days.
A huge flash arc mini-explosion blasted that screwdriver and left me seeing spots for a few hours.
The TLDR is at the input you limit lightning / hand of god level of voltages using the usual RF techniques for lightning protection, so you never have to protect against more than a couple hundred volts, then implement a ridiculously high impedance / voltage attenuator such that it'll arc over before the output exceeds a volt or so, then you limit the output with (optimistically) low capacitance diodes to the power supply. Then a buffer that converts from high impedance in to low output impedance and from there on its pretty boring analog stuff, gain stages etc.
Or the TLDR of the TLDR is you have multiple protection stages and (controllably) attenuate the heck out of the input signal. Also you rely on some ohms law tricks... a voltage big enough to damage in series with a ridiculous resistance will be a very low current which any protection diodes can survive.
Its a tricky business to work around all the RC time constants that occasionally are not fun at all.
Three things to think about. Everyone uses 10x 100x 1000x scope probes, so when you sniff 460V VFD power you're probably using a 100x probe and only measuring 5 volts or so. Also protection circuits tend to protect against the usual 60hz and DC overvoltages... shoving the output of a MRI amplifier at hundreds of MHz will just arc across and blow it to bits. Finally its possible to build RF front ends that sniff RF down to thermal noise limits, and scopes throw all that away to survive hundred volt transients on the input; I assure you ultra low noise microwave preamps will not survive more than a couple volts input, but those are bazzilionths of a picowatt not mV range.
Oh and a warning... you pick up a 100x scope probe, your scope handles up to 500 V input (perhaps) so you think you're good to 50000 volts in, but the probe has its own input voltage limit and unless you have bottomless pockets it probably tops out around 2.5 KV, so if you try to measure a 35 KV flyback transformer for an old fashioned CRT using that 2.5 KV probe, kaboom...
Don't store strong chemicals in your bedroom
"I had made some gunpowder and had some sitting on an outside table. I was experimenting with fuse design and was burning a fuse 6 feet or so away."
"I bought some H2SO4 and used most of it immediately. Unfortunately the original plastic bottle didn't fit in my cabinet. So I transferred the contents to a couple of small plastic bottles. Finally, the cabinet was temporarily blocked so I decided to temporarily store them on a shelf next to my bed."
"I had a few hundred mL of acetone and H2SO4 waste stored in a glass peanut butter jar."
He's incredibly bright (the X-ray machine with the 2D positioner is just plain brilliant) but he just doesn't seem to think far enough ahead.
I asked that a cardboard box blast shield be placed over the H/W before participating in further tests.
Wow. Just... wow.
So, I needed to swap the PSU because we planned to add more of them, and I plugged it out - and cut the supply cable with a scissor. Twelve capacitors blew out (I believe because the ICs turned off the power of the LEDs before the caps were discharged, they were ridiculously huge anyways)... right in the middle of school day, and a week before there was some retard running amok and killing students.
tl; dr: Shorted 12 caps, huge explosion sound, peoples panicked and thought of a school shooting.
Magic smoke needs a magic fume hood or being outside ;-) I can't say for sure, but I would err guessing a lot of smoke coming out of exploding or burning electronic components is not good for you.
I don't know how someone can get into chemistry before 18. I understand reactions that are presented to me, but how do you get the initiative of trying something new? How can I be confident those are the only reactions that happen? OP has only produced H2S by mistake a few times in his life, far fewer than I'd expect anyone experimenting to produce unexpected chemicals.
This is what kids do naturally, before they know any better. A lot of kids experiment with chemistry. The trick is keeping them alive and unmangled until they develop a respect for what they're working with.