nav[aria-label="Primary Navigation"] { padding: 0; & ul { list-style: none; width: 100%; display: flex; flex-direction: row; justify-content: start; align-items: start; gap: 30px; padding: 0; & li { margin: 0; } & ul li { list-style: none; } } }

Child Item

I bet you didnt know that

Cartouche

As people here work in various jobs / professions they might know things from work or study no one here knows yet. this is what this topic is about.

what do you know that we have never heard of?

Eg: you don't need to be great at maths to be an architect

this is obvious to me but everyone says to me "i wanted to be an architect but i was bad at math,i can barely add"

Find more posts tagged with

Quick Links

Comments

Grayson

I read this great article about Termites this morning on the way into work
https://www.theguardian.com/news/2018/sep/18/a-giant-crawling-brain-the-jaw-dropping-world-of-termites

The mass of all the termites on the planet is 10 times the mass of all the humans. Which means that for you, there is a mass of termites that's 10 times bigger. Thankfully you don't bump into that mass often

Grayson

Nixonbot wrote: »

The problem here is "approached". 0.999... doesn't "approach" anything, it is a static number. The thing is that the number of 9s is infinite. It literally never ends.

This one is pretty good:

https://www.purplemath.com/modules/howcan1.htm

For a layman like myself who forgot all his maths the second I left university

yep, although I didn't see any mention of analysis there. (Upper and lower bounds)

A simple way to think of the difference is this, there is a number that you can add to .99999..... that will equal 1. Therefore the two numbers are different. In practical terms you could say they're the same but you're rounding up. You're rounding up by an infinitely tiny amount but you're still rounding up.

The thing about maths is that it's quite often wrong. Even the basic rules we use are wrong sometimes. Here's another example.

Edit: I pasted that in before reading it properly. I just noticed the mistake in it

Wibbs

gozunda wrote: »

Birds excrete 'urine' in the form of urates (uric acids) - which are semi-solid and white in colour and a clear liquid.

Bird(and bat) poo AKA guano found and mined in large deposits in caves and islands where seabirds roosted for centuries drove 18th and 19th century intensive farming as it was the perfect fertiliser high in phosphates, nitrogen and the like. It was largely replaced by the late 19th and early 20th century chemical industry(mostly centred in Germany) that produced artificial fertilisers. Bat poo guano was occasionally used in the production of explosives because of it's high nitrate content.

One theory going is that importation of South American guano as fertiliser into Ireland in the 1840's brought with it a particularly nasty version of the potato blight that caused the Irish Famine.

Skylinehead

FishOnABike wrote: »

Explanation or link? I'm intrigued as I would have thought that it would approach 1 or the limit as the number of decimal places approached infinity would be 1.

The problem here is "approached". 0.999... doesn't "approach" anything, it is a static number. The thing is that the number of 9s is infinite. It literally never ends.

This one is pretty good:

https://www.purplemath.com/modules/howcan1.htm

For a layman like myself who forgot all his maths the second I left university

ohnonotgmail

FishOnABike wrote: »

Explanation or link? I'm intrigued as I would have thought that it would approach 1 or the limit as the number of decimal places approached infinity would be 1.

posts #7804 and #7805. The wiki page also explains it in several ways

https://en.wikipedia.org/wiki/0.999...

FishOnABike

Fourier wrote: »

Trust me I get the intuition, but bizarrely it exactly equals 1.

Explanation or link? I'm intrigued as I would have thought that it would approach 1 or the limit as the number of decimal places approached infinity would be 1.

ohnonotgmail

This, for me, is the easiest way to look at it

Skylinehead

I find the easiest, if reductive, explanation is that we all generally accept 0.333... = 1/3. Multiply both sides by 3 and you have 0.999... = 1.

Fourier

FishOnABike wrote: »

I would said it is more correct to say it approaches 1 rather than it equals 1.

Trust me I get the intuition, but bizarrely it exactly equals 1.

Sabre0001

IvyTheTerrific wrote: »

And that's not a new trick to catch out fraudsters.
Dictionary makers put fake words in dictionaries and map makers put false features on their maps so they can tell when they've been copied.

On a related note, there was a town in upstate New York that was a "paper town." Agloe was created by a mapmaker (Otto G. Lindberg, director of the General Drafting Co., and his assistant, Ernest Alpers) to catch anyone who copied their map.

When Rand McNally produced its own map of New York, this town was included. They defended its inclusion by stating that they had traveled there and found a general store. Turns out the owners of the store had purchased the original map and named their store after what Lindberg and Alpers called the area, and essentially created a town in the process.

https://www.npr.org/sections/krulwich/2014/03/18/290236647/an-imaginary-town-becomes-real-then-not-true-story

FishOnABike

Fourier wrote: »

The part in bold is true, but as a strange fact 0.9999... (9 repeating endlessly) does equal 1.

I would said it is more correct to say it approaches 1 rather than it equals 1.

sbsquarepants

Fourier wrote: »

The part in bold is true, but as a strange fact 0.9999... (9 repeating endlessly) does equal 1.

Even though I know this to be the case, it still feels like it should be just a tiny bit less!

gozunda

bodhrandude wrote: »

I bet you knew that its not hens that smell but their poo.

Birds excrete 'urine' in the form of urates (uric acids) - which are semi-solid and white in colour and a clear liquid.

Birds kidneys extract nitrogenous wastes from the bloodstream like other animals do. However instead of releasing it as urea dissolved in urine, birds excrete it in the form of uric acid. It comes out as a white sort of goo along with the faeces because of the biochemical reactions that happen to process the waste so it can be safely excreted with minimal water loss.

Wibbs

RIGOLO wrote: »

Is that a German or British 'Trench' watch ? Just curious , who were they given too.

That one is British. At that stage they were rarely bought by and issued from army stores in WW1(the Americans sometimes issued them. The US Signal Corp for example). They were almost all private purchases, mostly by the officer class as they were an expensive item. About the equivalent of ten weeks wages for the average worker. Some have engravings that show they were bought by groups of family and friends, or coworkers, for men going to war. Some were bought by groups of soldiers for sergeants and the like who they respected.

Generally at the start of the 20th century wristwatches were a very rare item for men. They were seen as a "woman's watch". Most men, if they had a watch had a pocket watch. By World War 2 militaries started to issue wristwatches to the average soldier as their tactical advantages were clear. Since many if not most ordinary enlisted men came from less well off backgrounds they didn't have a watch of their own, or they had a more dressy affair not suitable for military use. Most armies, allied and axis had such programmes. Some like the German examples were paid off as a deduction from the soldiers pay. The German issued time only watches cost about the equivalent of 7-800 euro today. US forces got them essentially free as part of their kit.

These days watches are rarely issued as a Casio costing a tenner will do the job and military time is ever present across radios and satnavs and the like.

Fourier

lan wrote: »

The values that they are off by are really tiny, but it can still cause problems, the most common are generally when converting them to a whole number (by default, a lot of programming languages will truncate a decimal instead of rounding) or when comparing them to numbers (0.999999 does not equal 1).

The part in bold is true, but as a strange fact 0.9999... (9 repeating endlessly) does equal 1.

lan

RiderOnTheStorm wrote: »

when I worked in IT we discovered a bug in one of the financial packages. After hours and hours of investigations we narrowed it down to the addition of two variables. One contains a value of 4, the other contained a value of 3, and when they were added together the sum was 6.999 ..... We fixed it, but never figured out why.

Computers can be a right pain!

Problems like this aren't actually that unusual, it's to do with how computers store 'decimal' numbers.

Most commonly, floating point numbers are stored in two parts, similar to scientific notation (e.g. x * 10^y), but in binary. Each part only has a limited number of bits (the exact numbers depends on the programming language and precision you use, but most follow the IEEE 754 standard).

Now think about how we represent 1/3 in decimal: 0.333333... You would need infinite digits. The same happens in binary too when trying to represent certain fractions, but the stored numbers have a very finite number of digits.

If you could only store 1/3 in 6 decimal digits, it would look like 3.33333 * 10^-1. Due to the loss of precision, if you then multiple it by 3, you get 9.99999 * 10^-1, not 1. Similar losses of precision can happen when you divide then multiply floating point numbers on a computer. This is a bit of a simplification, but I hope it gets the point across.

The values that they are off by are really tiny, but it can still cause problems, the most common are generally when converting them to a whole number (by default, a lot of programming languages will truncate a decimal instead of rounding) or when comparing them to numbers (0.999999 does not equal 1).

I can't speak to your exact problem, but it sounds like it was probably caused by something similar.

NIMAN

MikeyTaylor wrote: »

Vince Clarke (Erasure/Depeche Mode/Yazoo) does his songwriting on an acoustic guitar!
http://www.musicradar.com/news/vince-clarke-im-not-a-good-enough-keyboard-player-to-write-on-the-synth

When did he write his last hit single?

RIGOLO

Wibbs wrote: »

They do mention clocks, but radium dialled watches were going well into the 1960's. Then for luminous dials they went to Tritium. Far less "hot", but still radioactive. That went on into the 90's in standard form, with a foray into promethium in the 80's(very short half life to drive the glow, two years IIRC). Today you can buy Tritium dialled watches where the tritium is encapsulated in vials to reduce the exposure by a large amount(down to basically nothing).

With all these "luminous" dials, the radioactive substance itself doesn't luminess, it charges the phosphorescent material mixed with it. You know your usual luminous watch these days that glows after exposure to the sun? Well the old style radium/promethium/tritium takes the place of the sun. Radium was so active it burnt out the phosphorescent material within a couple of years(early wiristwatch adverts guaranteed two years glowing). However, even though the old dials don't glow anymore, the radium, with (IIRC) a half life of over 1500 years is still as active and potentially deadly today.

Here's one of my personal hoard of World War One "trench" watches. Avec radium dial.
.

Is that a German or British 'Trench' watch ? Just curious , who were they given too.

MikeyTaylor

Vince Clarke (Erasure/Depeche Mode/Yazoo) does his songwriting on an acoustic guitar!
http://www.musicradar.com/news/vince-clarke-im-not-a-good-enough-keyboard-player-to-write-on-the-synth

Ten of Swords

Capt'n Midnight wrote: »

There have been 11 children born in the Antarctic territories, the first birth occurring in 1978.

Between 1978 and 1983 there were 8 births in Esperanza Base (Argentine Sector) and between 1984 and 1985 there were 3 births at Presidente Eduardo Frei Montalva Base (Chilean Sector)

The precedent for treating citizenship issues was set at the birth of the first baby Emilio Marcos Palma in 1978. As the Argentine claim zone is not officially recognized internationally, and partially overlaps the British claim zone, his place of birth is inside the disputed zone. He has the right to British Overseas Territory citizenship under the terms of British Antarctic nationality law - but his parents never made any attempt to claim it so instead he is legally a citizen of Argentina by right of the legal concept jus sanguinis (right of blood) as the legal concept of jus soli (right of soil) does not apply to Antarctica.

Water John

We're not going. If you insist you can come down and say it to Roy Keane next Tues at Liam Miller match.

[Deleted User]

Wibbs wrote: »

IIRC Radium is a bugger because its a heavy gamma producer. Tritium's output would be stopped by the case and glass of the watch. The only real risk would have been to watchmakers who had to open the case to service the movement. The radium mixes also broke down like a bugger. Extremely hygroscopic, so suck up the damp from the atmosphere, which makes them break down even more. into dust that permeates everything. Dust you really would not want to breathe in. Would make a 60 a day ciggie habit look healthy.

Years back in the 90's a watch of mine from the 1930's was tested by a lass I knew who was writing up a paper on radioactive sources in the home and was described as "low level nuclear waste"(she got quite panicked. And she wasn't the type). I got the dial cleaned and reprinted, but the movement also needed to be stripped right down and cleaned as it was emitting radiation of its own from the accumulated dust. As a kid I regularly used to wear that watch to bed as the loud ticking calmed me....

Me. Earlier.

:eek:

Ah, the auld phosphorous numerals on clocks. My parents refused to have any in our house as they said it had radiation which could possibly cause cancer. My friend down the road had one in her house, and I told her what my parents had told me. She looked up horrified at the thing glowing down at us from the mantelpiece. She thought of turning the clock face to the wall, but knew her father would quickly notice that. She said “we children shouldn’t be exposed to that as we are only growing. Maybe if I turned the clock to face Aunty’s chair it would be best as it would be facing away from Dad’s chair, and it wouldn’t matter as much if she gets cancer as she has no children”. Her Mum was always in the kitchen, never time to sit down on the settee in front the cancer-giving clock.

Realt Dearg Sec

Water John wrote: »

An Outpost of the Peoples Republic of Cork.

Maybe we can move them down there!

Cookie_Monster

mzungu wrote: »

The only non-human or puppet to testify before Congress was Elmo in 2002. He was making an appeal for increased funding for new music education programmes.

far from the only muppet to testify though :pac:

[Deleted User]

Realt Dearg Sec wrote: »

Jaysus, with the amount of random countries laying claim to the place, we might as well just declare a chunk of it to be Irish. Sure why not? I don't see any good reason why Britain would have a better claim than we would.

Uk have the most exciting and easy to reach bit for the ordinary Joe Soap. Stunning place! Ukraine were given a tiny outpost on an island, where they make salty vodka and the only souvenirs actually made in Antarctica.

mzungu

The only non-human or puppet to testify before Congress was Elmo in 2002. He was making an appeal for increased funding for new music education programmes.

Elmo-Washington.jpg?resize=777%2C437&ssl=1

Elmo-Washington.jpg?resize=777%2C437&ssl=1

Water John

An Outpost of the Peoples Republic of Cork.

BaZmO*

Realt Dearg Sec wrote: »

Jaysus, with the amount of random countries laying claim to the place, we might as well just declare a chunk of it to be Irish. Sure why not? I don't see any good reason why Britain would have a better claim than we would.

Well the first person to discover it was an Irish man from Cork.

“Edward Bransfield was an Irish sailor who rose to become an officer in the British Royal Navy, serving as a master on several ships, after being impressed into service at the age of 18 in Ireland. He is noted for exploring parts of Antarctica, sighting the Trinity Peninsula in January 1820.”

Tom Mann Centuria

On a vaguely similar theme (equally depressing anyway), workers, women and children particularly, who worked in match factories in the late 19th early 20th century, were prone to phosphorus poisoning.

It could lead to multiple problems, one of the worst being phosphorus necrosis of the jaw, as the name suggests, it disintegrated the bottom jaw. They also glowed in the dark.

Wibbs

Carry wrote: »

A horrible death for the sake of luminous clock-faces.

The watches were much worse C. Because the numerals were so small, they were instructed to point their brushes by first wetting them with their lips and the ingested crazy levels of radium this way. So may died, but they fought hard in the courts until they did. A landmark case in worker's health. In the face of the 19th century attitude towards workers as glorified slaves. Never mind women workers. Those "radium girls" were true heroines of humanity, the lot of them. Most died and died appallingly, but for me personally what fascinates is quite a few didn't die at the time and a couple lived normal length lives. People differ I suppose.