Spyke
startrek.website

"The length of the path travelled by light in vacuum during a time interval of ⁠1/299792458⁠ of a second, where the second is defined by a hyperfine transition frequency of caesium."

This is the actual definition, but it's also pretty weird.

44
slazer2aureply
lemmy.world

And here I thought it was that sick of metal in the wall in France when it is 21 degrees C

13
Björnreply
swg-empire.de

They redefined it a few years ago to base all units on some objectively measurable natural constant. Because that stick of metal might still decay or warp or something and you don't always want to travel to France when you want to know the length of a meter. Much easier to measure the atoms and light you have on hand.

12
Natanaelreply
infosec.pub

Updating the kilogram standard took them forever because you need really reliable force measurement instruments and very precise calibration

5
slazer2aureply
lemmy.world

Hey, just because I am Australian doesn't mean I am a crime of nature. That is just our animals.

6

It was defined as

one ten-millionth of the shortest distance from the North Pole to the equator passing through Paris.

The stick of metal in Paris is just so people don't have to do measure the distance between the north pole and the equator each time they want to check their measuring tool.

3

look it's not like there's a titanium standard dude lodged somewhere in a vault in France, but I reckon we all know the difference between a short dude, a long dude, and a metric regular dude

3
lemmy.world

Depends on the meter, dude. There are thermo-meters, speedo-meters, baro-meter...

33

Take a really long rope and put one end on either pole of the Earth, and the other end on the equator. Use the shortest path, and make sure the rope is tight. No squiggles allowed! Chop that rope into exactly 10 000 000 equal parts. One of them is as long as a meter. Now you just need to find the right one.

Edit: more zeros.

22
pmkreply
lemmy.sdf.org

Distance between pole and equator is... 10 km?

6

A bit more than 90 centimetres, a bit less than 110. Somewhere in that ballpark.

14
feddit.org

Okay, so, right, okay. Um. In German schools (and probably some other countries...?), many many years ago (possibly still today? or maybe it's all digital now? what am I saying, this is German schools), the blackboard in every classroom was a large, green, rectangular middle part and two square "wings", one on each side (as wings are wont to be...). They can swing in and out, providing extra room for writing on the outer side of the wings. Also for extracurricular shenanigans such as writing "[name] + [name] = SEX" in the middle, swinging the wings closed to hide the writing and then breaking out into hysterics when the teacher opens the blackboard to reveal your incredibly highbrow joke.

This type of blackboard is quintessential to my recollections about and concept of school.

Why am I going into such unnecessary detail about this? I have ADHD and possibly autism, I need you to understand what I'm saying and I can't find any sources of this existing in the English speaking world and I can't find an English word for those "wings" either. I can barely find a German one ("Tafelflügel"? I don't think it's ever come up before in my life).

So here's a picture:

The width/height of the "wings" and the height of the middle part, that's a metre. Thank you for coming to my TED talk.

12
Peterssonreply
feddit.org

Does the metallic edge count as part of the meter too or just the green surface? What if it's so hot the wings expand?

5
Lumidaubreply
feddit.org

Just the green. This is special German engineering high-tech space material whose name I absolutely do know but am not at liberty to divulge and that doesn't expand (i.e. I've never experienced a blackboard being warmer than slightly cool to the touch).

3
Peterssonreply
feddit.org

Is there an ultimate ancestor of all boards by which you can detemine if your board actually has the correct 1m height? Do we even need such a board if we accept Constructivism?

3
Lumidaubreply
feddit.org

Are you... are you putting the word of my primary school teacher into question? How DARE you?!

4
Peterssonreply
feddit.org

I dare by being the last row's kid never accepting anything. You didn't answer my questions, so here's just one this time: How wide has each letter of Rindfleischetikettierungsüberwachungsaufgabenübertragungsgesetz to be so it fits on the board?

E: Typo writing Rindfleischetikettierungsüberwachungsaufgabenübertragungsgesetz

4
Lumidaubreply
feddit.org

Typo writing Rindfleischetikettierungsüberwachungsaufgabenübertragungsgesetz

If you can't take this seriously for even one second and follow basic German Rechtschreiberegeln, you don't deserve any answers.

4

Sorry, there was an

at the wrong place.

I'm taking it completely serious, do you?

3
Peterssonreply
feddit.org

I didn't even know what a M16A4 is. Some US unit, right?

9

Yes, with the official M16A4 unit being defined as 1/100th the length between the goal lines of an American Football field.

10
lemmy.world

Try to piss as far as you can. Now you know how long a meter is.

8
Peterssonreply
feddit.org

But how do we measure the lenght? Do we have to find a way which includes the last drop? And what if I don't have a penis?

3
rustyfishreply
lemmy.world

You piss in the snow to clearly see the pee and the furthest drop counts.

If you don’t have a cock you are free to bring a dick you trust to the measurement. Just make sure to fill the form A38 beforehand and your designated piss officer will give your team green light.

5

Can some non-German person please fill out the A38 in English without translating a single German word of the A38?

6
lemm.ee

Only weird answers?

The truth itself is weird: The meter is defined as the distance that light travels in a vacuum in 1/299,792,458 seconds.

7
Victorreply
lemmy.world

The problem is that the meter is originally defined in terms of the size of the earth, which is in no way related to the speed of light.

5
Victorreply
lemmy.world

Well yes, but only by a little. It was using ancient measuring techniques which were highly error-prone. Like running from one place to the next and counting the length manually. Shit like that. Still impressively close to the real size!

1
programming.dev

But if the people deciding what the meter was at first were allowed to make errors, why werent the people deciding what the new meter was?

1

But if the people deciding what the meter was at first were allowed to make errors

It's not that they were allowed to make errors, it's more like they made errors and didn't know any better.

why werent the people deciding what the new meter was?

They may very well have made a mistake, and we just haven't noticed yet.

1
Victorreply
lemmy.world

Like what the other person said, you don't know the extent of your error until you have a more accurate measuring technique.

And you don't just redefine an already-established unit. 😅 Rather, all the things that depend on the meter will be fucked up instead.

1

But it would be wrong by only 1% and it would make the speed of light so much more easy to use and remember

1

take a meter stick, now cut it in half. glue it back together. a meter is probably a little bit longer than this since you lost some material cutting.

5
discuss.online

Well, meter, like atom meter? Or like gas meter? Anti meter? You need to specify the type of meter.

4
lemmy.dbzer0.com

Take one liter of water at "room temperature" an aprox of 20 Celcuis degrees at one atmosfere pressure. Take a straight transparent tube of one centimeter inner thickness. Put the water in without spilling.

Measue...

A meter...

4

That's wrong. The tube has a cross section of 0.25π cm² so your tube will be filled ~1,2732m high.

Also as others have stated, if you can measure 1cm you already have a definition of a Meter.

2

you will have measured 1.00005 meters (sqrt(1+0.01²)), assuming your eyes are the best in the world.

2

how am I supposed to measure the inner thickness?

1

Hold one arm on your body and stretch the other one to your side. Now make your wrists/hands point forward. This is a meter.

4

The distance that light travels in about a three hundred millionth of a second. Wait, that's just the actual definition.

4

I think we can agree there are large and short meters. So everyone is right.

4

About as wide as my oversized fridge.

Can't wait to get rid of that shit and have something that actually fits in my kitchen.

3

My meter is about six inches by three (from memory). It measures voltage (both AC and DC) and current.

3

The distance between the first line in a hopscotch game and where I would put the top line of the [4, 5] block.

3

It's more than less than a meter but less than more than a meter.

2

It takes 20s for falling cherry blossom petal to travel.

2

From the tip of your right thumb to your left nipple. Too sensible?

1

There are 5 meters in one Iambic pentameter, so one meter is 0.2 of those.

1

You mean the the square root of the surface of Saarland divided by 2,569,690?

4