Science New Definitions of SI Units in 2019 - Uncouth Americans can safely ignore

From Nature.com.

Revamped definitions of scientific units are on their way. In the biggest overhaul of the international system of units (SI) since its inception in 1960, a committee is set to redefine four basic units — the ampere, the kilogram, the kelvin and the mole — using relationships to fundamental constants, rather than abstract or arbitrary definitions.

The changes would take effect in May 2019.

The kilogram is currently defined as the mass of a chunk of metal in a vault in Paris. And an imaginary experiment involving the force between two infinite wires defines the ampere, the unit of electrical current. The mole, meanwhile, is the amount of substance in a system with as many elementary entities as there are atoms in 0.012 kilograms of carbon-12, while the kelvin relates to the temperature and pressure at which water, ice and water vapor co-exist in equilibrium, known as the triple point of water. In the future, these units will be calculated in relation to constants — for example, the ampere will be based on the charge of an electron, while the kilogram will be defined with respect to the Planck's constant, a fundamental in quantum mechanics.

 

[DeadwastePrime]

From Nature.com.

Revamped definitions of scientific units are on their way. In the biggest overhaul of the international system of units (SI) since its inception in 1960, a committee is set to redefine four basic units — the ampere, the kilogram, the kelvin and the mole — using relationships to fundamental constants, rather than abstract or arbitrary definitions.

The changes would take effect in May 2019.

The kilogram is currently defined as the mass of a chunk of metal in a vault in Paris. And an imaginary experiment involving the force between two infinite wires defines the ampere, the unit of electrical current. The mole, meanwhile, is the amount of substance in a system with as many elementary entities as there are atoms in 0.012 kilograms of carbon-12, while the kelvin relates to the temperature and pressure at which water, ice and water vapor co-exist in equilibrium, known as the triple point of water. In the future, these units will be calculated in relation to constants — for example, the ampere will be based on the charge of an electron, while the kilogram will be defined with respect to the Planck's constant, a fundamental in quantum mechanics.

wtf is mole unit for?

 

[ICametoLurk]

wtf is mole unit for?

If it's not being used to determine if Jamal is Jewing you and deserves his arms and testicles blown-torched off, it's something that you can live your life without knowing.

 

[XYZpdq]

wtf is mole unit for?

That's when the International Rescue team needs to get underground. They deploy it from Thunderbird 2, I think.

 

[Positron]

wtf is mole unit for?

This unit converts macroscopic weight (e.g. gram) to the number of atoms or molecules, useful in Chemistry.

For example you want to make ammonia. From the equation:

N2(g) + 3H2(g) <--> 2NH3(g)

You see you need nitrogen and hydrogen molecules in a ratio of 1:3, but the problem is, you can't see molecules and you sure can't pick them and sort them out; you can only weight the gases in kilograms or tons. So how can you be sure you have the correct ratio? That's when you have to talk in terms of moles. You know need one mole of nitrogen gas and three moles of hydrogen gas, and you can find out the weight by checking the periodic table.

 

[DeadwastePrime]

This unit converts macroscopic weight (e.g. gram) to the number of atoms or molecules, useful in Chemistry.

For example you want to make ammonia. From the equation:

N2(g) + 3H2(g) <--> 2NH3(g)

You see you need nitrogen and hydrogen molecules in a ratio of 1:3, but the problem is, you can't see molecules and you sure can't pick them and sort them out; you can only weight the gases in kilograms or tons. So how can you be sure you have the correct ratio? That's when you have to talk in terms of moles. You know need one mole of nitrogen gas and three moles of hydrogen gas, and you can find out the weight by checking the periodic table.

and they didnt bother teaching that in school?

 

[Takayuki Yagami]

and they didnt bother teaching that in school?

They do. Doesn't everyone have to take chem in high school?

 

[DeadwastePrime]

They do. Doesn't everyone have to take chem in high school?

they didnt teach that at my school

 

[Organic Fapcup]

they didnt teach that at my school

Maybe you just nodded off during chemistry

 

[Faber]

they didnt teach that at my school

You've been jewed. If you've never heard about moles you know next to nothing about chemistry, you've never had any fun with pH indicators and wacky acids and they never let you blow up anything.

Let me guess, they did have time to teach you about several gay beat poets and all of history's angry lesbians.

 

[XYZpdq]

I vaguely recall learning that in high school but I don't make meth so fuck remembering high school science classes.

 

[Doc Cassidy]

Metric system lol

 

[Autopsy]

You've been jewed. If you've never heard about moles you know next to nothing about chemistry, you've never had any fun with pH indicators and wacky acids and they never let you blow up anything.

I pity those who will never learn the simple joys of GAS LAW because they've been deprived an education.

Edit: Just did some digging, these changes are the ones they've been cooking for the past few years, not something new.
Essentially, they're trying to shuffle around the uncertainties. At the moment, most constants are expressed with uncertainty and the equations are 'exact'. These changes will lead to constants being 'exact' with equations taking on the uncertainty. It's all more or less QM shilling, but that's not the worst thing in the world.

 

[Chemical snorfare]

I can see this costing money.

I'll put off buying any new fuses for a while.

 

[GentlemanFaggot]

You've been jewed. If you've never heard about moles you know next to nothing about chemistry, you've never had any fun with pH indicators and wacky acids and they never let you blow up anything.

They don't let you have fun in most high school chemistry classes.

For me, it was more like, "Okay, pour this chemical into another and watch it fizz. Oooooh, aaah, wasn't that great? Now let's pour another into another and watch it fizz. And then another and another..."

The teacher would also vanish from class and drink.

 

[AnOminous]

They don't let you have fun in most high school chemistry classes.

For me, it was more like, "Okay, pour this chemical into another and watch it fizz. Oooooh, aaah, wasn't that great? Now let's pour another into another and watch it fizz. And then another and another..."

The teacher would also vanish from class and drink.

My favorite chemistry teachers were the ones who would catch shit on fire and have explosions. And dissolve shit in hydrofluoric acid. And, I dunno, sometimes have unexplained disappearances from class to return a couple minutes later, strangely flushed and even more enthusiastic about blowing shit up.

Modern students have been truly robbed by the fact teachers' unions vehemently oppose paying STEM teachers more than useless teachers, even though STEM teachers are objectively better for society. These whacked-out crazy fucks I had as science teachers would never work at a school these days. They'd go into the private sector and make bombs and shit.

 

[CWCchange]

I vaguely recall learning that in high school but I don't make meth so fuck remembering high school science classes.

Same here. The only thing that really stuck with me was the rote about King Henry dying Monday drinking chocolate milk.

 

[An Ghost]

This makes sense. The problem with using a chunk of metal as a reference point for weight is it has a half life. Eventually it gets lighter. Using a constant is good. A kilogram won’t change now and it’ll never change.
Ps americunt here but in science fields so this matters to me.

 

[Quack]

I really think more constants should be defined in terms of old buildings in London. They have brass knobs sticking out of a wall at the Royal Observatory that say they are one foot apart, and that's good enough for me. Also, metric is a Catholic plot.

 

[Audit]

This is good news. Perhaps my country will finally leave its barbaric imperial units behind and enter the modern world. I'm tired of explaining the difference between pound mass and pound force to people.