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How I got my laser eye injury

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Re: How I got my laser eye injury

#341

Post by specialist »

harshreality wrote: post #336
lupusreal wrote: post #321

Earlier quoted context omitted.

I just nuke a mug of water for a minute or two when I'm making instant coffee. I never understood the big deal about electric kettles.

A water kettle lets you consistently heat water to the same temperature (not just boiling, high-end kettles have additional temperature options), regardless of: - Amount of water - Initial temperature of water - Position of water container They also prevent superheated water accidents.

Yes and: Kettles are much easier to clean than microwave (interiors).

Re: How I got my laser eye injury

#342

Post by SonOfLilit »

msrenee wrote: post #285
SonOfLilit wrote: post #254

Earlier quoted context omitted.

PSA: Sharks die quickly if you get them still. Their heartbeat is connected to the swimming motion.

Some sharks have to swim to move water over their gills. Not even close to all of them and it's not due to their heartbeat being connected to their swimming. https://www.britannica.com/story/do-sharks-really-die-if-the...

Thanks. In my defense, I heard this from my diving instructor who is a marine biologist.

Re: How I got my laser eye injury

#343

Post by jtwaleson »

meindnoch wrote: post #173
cowthulhu wrote: post #164

Earlier quoted context omitted.

Are lasers typically able to reflect off of surfaces that diffuse light (ie drywall)? I’m totally ignorant when it comes to laser safety, apologies if this is a stupid question .

Do you see a bright spot when aiming the laser at drywall? If the answer is yes, then laser light is being reflected into your eye. Hope this helps!

I’m confused. This is true from every angle from which you look at the wall right? So there has to be quadratically less reflection than e.g. a mirror, but still a lot more then a completely black surface.

Re: How I got my laser eye injury

#344

Post by cesarb »

beAbU wrote: post #276
ruined wrote: post #257

Earlier quoted context omitted.

british household AC is wild, it's like they've got a full-power american range plug for every outlet

Not just UK, the whole world except North America and Japan. South african plugs are rated 16A @240V. Thats a safe 3.5kW at each and every plug socket in the house.

> Not just UK, the whole world except North America and Japan.

Brazil is also an exception. The standard socket is only 10A (with a 20A alternative for things like air conditioners), and the voltages vary depending on the city (and the building, and location within the building); you might have 110V, 115V, 127V, 220V, 230V, and perhaps others I have missed (I went in more detail about it at https://news.ycombinator.com/item?id=40385851). I live in a 127V/220V area, so my single-phase sockets are 10A @ 127V, for a total of only 1.3kW each.

Re: How I got my laser eye injury

#345

Post by BizarroLand »

gcanyon wrote: post #309
sho wrote: post #287

Earlier quoted context omitted.

It's actually only americans who unaccountably make do with these horribly underpowered kettles. The rest of the world wants their tea and they want it now...

Technology Connections did an excellent video on this: https://www.youtube.com/watch?v=_yMMTVVJI4c tl;dw -- kettles in the U.S. only take about 4+ minutes to boil a liter of water. So when you say "now" you really mean it.

I live in the US and have an induction stovetop. It can dump 3600 watts of targeted heat into a pot of water. It can boil 2 liters of water in ~3-5 minutes.

Plus, when you reduce the heat the heat reduces almost immediately.

Nothing else compares with the speed it works that I've ever used before. Definitely worth the upgrade in time saved at the stove.

Re: How I got my laser eye injury

#346

Post by dublinth »

RandomThoughts3 wrote: post #168
dctoedt wrote: post #103

Earlier quoted context omitted.

> hull damage being caused or not caused by a rifle being fired from the flight deck of a ship How did that happen? Our MarDet would occasionally do live-fire training off the flight deck (CVN-65); they naturally pointed their weapons away from the ship .... Or are you talking about hitting the hull of a different ship, e.g., one of the tin cans in plane guard, or alongside during an UNREP? Seems like that would ...…

Hypothetically, someone could have left a guest (like say an engineer from the shipyard doing sea acceptance testing) fire a rifle and an unlucky wave reflection might have bounced a round back towards the bow.

"A wave? At sea? Chance in a million."

Re: How I got my laser eye injury

#347

Post by meindnoch »

jtwaleson wrote: post #343
meindnoch wrote: post #173

Earlier quoted context omitted.

Do you see a bright spot when aiming the laser at drywall? If the answer is yes, then laser light is being reflected into your eye. Hope this helps!

I’m confused. This is true from every angle from which you look at the wall right? So there has to be quadratically less reflection than e.g. a mirror, but still a lot more then a completely black surface.

The inverse squared falloff from a diffuse surface is not enough to prevent eye damage if you're in a regular-sized room, and playing with a class IV laser, or even some class IIIb lasers (depending on the distance, and the duration).

Re: How I got my laser eye injury

#349

Post by cwillu »

maldie wrote: post #334
sebastiennight wrote: post #249

Earlier quoted context omitted.

This seemed like a wild claim (2500 watts for a tea kettle!? As much as a microwave oven in full blast?) so I looked it up. Wow.

Interesting what power do microwaves in US deliver. In EU the regular micros are about 900W range give or take 200W (that is 1500W from wall because microwaves are not efficient machines) but kettles have usually range 2200..3000. So it is obvious why everyone uses kettles. I myselft have 3kW one and it heats 0.35 litres to boiling in 51 seconds. To have similar microwave it would have to be 3000W micro that is 4500W…

Standard wall outlet in the US is 15 amps, so a maximum of 1800 watts. 20 amp outlets (which can supply 2400 watts) are getting common, but I've seen very few home appliances that actually use the extra amperage (as determined by having a plug keyed for such an outlet).

Re: How I got my laser eye injury

#350

Post by yencabulator »

maldie wrote: post #334
sebastiennight wrote: post #249

Earlier quoted context omitted.

This seemed like a wild claim (2500 watts for a tea kettle!? As much as a microwave oven in full blast?) so I looked it up. Wow.

Interesting what power do microwaves in US deliver. In EU the regular micros are about 900W range give or take 200W (that is 1500W from wall because microwaves are not efficient machines) but kettles have usually range 2200..3000. So it is obvious why everyone uses kettles. I myselft have 3kW one and it heats 0.35 litres to boiling in 51 seconds. To have similar microwave it would have to be 3000W micro that is 4500W…

A typical US microwave draws 900-1100 watts too. I can't even find a 2000-watt microwave listed for sale in the usual consumer places. That'd be like a "pro chef" level luxury item, likely needing beefier electrical wiring and so on. US electric code requires a dedicated 20-amp circuit for microwave, which isn't supposed to serve a 2000-watt load.
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