When the battery connected:
this post was submitted on 23 Nov 2023
606 points (95.9% liked)
Memes
45585 readers
1836 users here now
Rules:
- Be civil and nice.
- Try not to excessively repost, as a rule of thumb, wait at least 2 months to do it if you have to.
founded 5 years ago
MODERATORS
An AAAA cell has 200-350 mohms internal resistance. A 9v battery has 6 of them in series (many of them are literally that, others have their cells as a stack of plastic buckets). The nose ring is a short run of wire, it's idunno a 0.2 ohm heater?
I think the septum is going to get pretty toasty.
I just tested this (for science!) with a 9V battery and an iron nail of roughly nose-ring diameter. Both the nail and the battery get unpleasantly hot after several seconds. I don't think they'd get hot enough to burn you, though. (Don't take my word, though, please!) I believe the internal resistance of the battery does also increase with the temperature, so it effectively somewhat self regulates itself.
Common nose ring materials like Titanium and Stainless Steel are 4× and 7× more resistant than iron, which means they should dissipate more power than the nail, and thus get hotter. I was calculating something around 3 milliohms for a titanium 16 gauge 10mm wire, and 0.7 milliohms for an iron wire.
Regardless of material, at 1000 milliohms internal resistance, i think the battery itself is doing most of the heat dissipation. (But also over a much bigger surface area!)
How long did you keep the nail on the battery for?
A 9V battery can be used as a foam cutter.
Styrofoam and most art foams melt at about 200°C
About 10-20s, I left it on until it didn't seem to be getting much hotter. I also didn't want the battery to overheat and fail catastrophically. I think because the "wire" is such a large gauge, there's not enough current for it to get seriously hot. In a foam cutter, you're passing all that current through a much smaller cross-sectional area.
Edit: just to confirm, I did a little math. A 10cm steel wire with a tenth of the diameter would have a resistance of 5 ohms. That means that instead of 1% of the total heat dissipating in the thick wire, 80% of the heat is dissipating in the wire in foam cutter's case, and there's more total resistance, so more heat dissipation as well.
This is because:
A = π r²
R = ρ × L / A
So resistance is proportional to the material resistivity (ρ), the length (L), and the inverse square of the radius (r⁻²). That is to say, decreasing the radius by a factor of 10 increases resistance by a factor of 100.
Here is an alternative Piped link(s):
https://piped.video/4Hj9PJstexk?si=_NEMZZU4Yu_CSN0a
Piped is a privacy-respecting open-source alternative frontend to YouTube.
I'm open-source; check me out at GitHub.
/c/theydidthescience
Thank you for your service
Well now I want to try this with my septum piercing and find out
Do it with the piercing OUT OF YOUR BODY. You don't want a hot piece of metal that you can't get off of yourself fast enough.
You could put one in a hot dog and shock it if you want to try it without making your nose toasty
If you do please let me know what happens lol.
Wakey wakey, septum bakey
Would the person feel anything? Presumably the electricity would flow through the metal as path of least resistance?
You don't shock the person.
You heat up the metal until it burns them.
I used to burn paper with a 9 volt and a paperclip. Good times
It's a short, the metal would heat up extremely fast and burn.
Yes, it would heat up. It would not be pleasant
They prob wouldn't get shocked but the ring and battery will get very hot very quick as there i pretty much no resistance wich means there is a lot of current flowing.
Someone else in the comments claimed to have calculated a resistance of 0.2 ohms.
I=U÷R
9V ÷ 0.2Ω = 45A
45 amps is a lot of current to flow through a nose ring. I don't know how much that is in heat but i'd expect you to get burned from it
You won't get more than a few mA out of an alkaline, but heat does build up. (Internal resistance)
A NiMH on the other and can give over 10 amps. They're a seriously risky thing to leave around loose metal bits. Or attached to thin wires.
Definitely won’t get shocked. I’ve run estim through nipple piercings and no shocks
Just put a 9volt in your pocket with some change
You're doing it wrong. You gotta place a metal sphere close to it connected to a Van de Graaff generator.
Cursed welding