# International Scientific Units

Can you name the units and prefixes used in the International System of Units (SI)?
Litres are not an SI unit
http://en.wikipedia.org/wiki/International_System_of_Units
Quiz by Quizmaster
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Last updated: October 21, 2016
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 First submitted January 22, 2012 Times taken 115,406 Average score 49.0% Rating 4.95
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 Base Units m Metre kg Kilogram s Second A Ampere K Kelvin mol Mole cd Candela
 Derived Units rad Radian sr Steradian Hz Hertz N Newton Pa Pascal J Joule W Watt C Coulomb V Volt F Farad Ω Ohm
 Derived Units S Siemens Wb Weber T Tesla H Henry °C Degree Celsius lm Lumen lx Lux Bq Becquerel Gy Gray Sv Sievert kat Katal
 Prefixes Y Yotta Z Zetta E Exa P Peta T Tera G Giga M Mega k Kilo h Hecto da Deca
 Prefixes d Deci c Centi m Milli µ Micro n Nano p Pico f Femto a Atto z Zepto y Yocto
+21
Level 43
Aug 22, 2014
nice to see a quiz that the chat is actually intelligent and not someone arguing.
+34
Level 75
Mar 21, 2021
Allow Kalbahamut to introduce himself lol ⬇️
+4
Level 50
Oct 15, 2022
his comment is right beneath this too lmao
+2
Level 60
Jan 24, 2024
That's why AlexThirkell wrote their comment. kalbahamut posted in 2014. AlexThirkell wrote theirs in 2021.
+1
Level 82
Aug 22, 2014
Liters are not an SI unit? Then why is one liter of water 1 kg at normal Earth gravity?
+44
Level 70
Aug 22, 2014
You got pretty mixed up. First: 1L of water is 1kg anywhere, because mass doesn't depend on gravity. And second: a liter is 1 cubic decimeter, the base unit is the meter. It could appear as a derived unit, the quizmaster just didn't feel like it
+18
Level 73
Jul 16, 2016
In SI terms it's "litre" and "metre"...as is the spelling and pronunciation of Aluminium
+10
Level 82
Aug 22, 2019
grantdon: that's just demonstrably false. There is no official spelling or pronunciation for liter, meter, or aluminum in SI, British and American English are both acceptable as are variations on these terms used in any other language, and the ones that you favor are not more correct or more international than any other variety. It's a little sad that this is what you're left with clinging to to avoid feeling insignificant.
+4
Level 75
Dec 12, 2023
I can't believe you just said that grantdon saying something random he thought was right has "left with clinging to to avoid feeling insignificant" I feel like that's a bit of a jump there
+3
Level 69
Aug 5, 2021
Allow Miqueas to introduce themselves lol ⬆️
+7
Level 58
Sep 5, 2021
The unit of measurement for length is a metre…a meter is a device that measures a unit like an ammeter, voltmeter, pedometer, speedometer, odometer seismometer etc.
+2
Level 60
Mar 16, 2024
so if i had a stick exactly one metre long and i used it to measure distance would that be a metre meter?
+1
Level 52
Jun 18, 2024
Technically speaking that would be a gauge as you won't get any measured values from that stick ;)
+3
Level 82
Aug 31, 2014
Okay. Haven't been to Physics class in a while.
+1
Level 86
Oct 16, 2014
The meter has been defined as a ten millionth of an half meridian (which is why the circumference of the earth is so close to 40000km...). Then the kg has been defined as the mass of a liter (= cubic decimeter) of water at ambient temperature. Note that gravity has no incidence on that definition, but temperature has: density varies according to temperature, this is what is called thermal expansion. These concepts were not mastered around 1800 when the units were defined, which is why a liter of water is not exactly one kilogram at 20°C. Since 1875, the exact definition of the kilogram is... the international prototype kept in Sèvres. It's frustrating that we have not been able to find something better since then but it's like that...
+1
Level 86
Oct 16, 2014
On the other hand, the second has been given a precise and complex definition, based on the hyperfine quantum levels transitions of the atom of Cesium. Then, since the speed of light is a very precisely known physical constant, the meter is simply defined as the distance travelled by light in a 1/299,792,458 of a second.
+3
Level 85
Sep 24, 2015
...in a vacuum. Also, between 1960 and 1983, a meter was defined as "1 650 763.73 wavelengths of the orange-red emission line in the electromagnetic spectrum of the krypton-86 atom in a vacuum."
+4
Level 68
Oct 28, 2021
Y'all are nerds.
+1
Level 31
Jun 15, 2022
Yeah, pretty much. I am only 13, but I know how time dilation works, and how to theoretically create a wormhole and how to time travel, which by the way, is impossible. You need to have a decent source of gravity with some exotic matter with negative mass in the middle and some kind of large, pulling force, such as a black hole, on the other side. But, since exotic matter and matter can't technically co-exist in the same plane of existence without creating a massive explosion producing 4.5e+35 joules of energy, depending on how much matter you pump into the equation, you would need an electromagnetic force keeping the individual atoms apart just enough that they don't spontaneously combust, but do their job and keep the time rift open.
+1
Level 45
Aug 22, 2014
2:05 left. Challenging, thanks!
+2
Level 77
Aug 22, 2014
It's my own fault but, when Amp didn't work I didn't bother trying Ampere. I always use the abbreviation.
+2
Level 72
Aug 23, 2014
Please can you accept amp for ampere, it's commonly referred to as just an amp.
+3
Level ∞
Aug 23, 2014
Okay
+4
Level 70
Dec 11, 2018
Really??? I dont think abbreviations should be allowed. Then you should accept sec and gig newt etc. The question is where do these letters stand for, not what do these letters stand for, that stands for the correct names. (If you get what I mean)
+13
Level 62
Apr 15, 2019
amp is a very common abbreviation that most people know ampere by.
+3
Level 70
Mar 28, 2020
Must be a regional thing then, here nobody uses that (in speech, writing it down they might)
+1
Level 53
Mar 9, 2024
I don't know where "here" is for you but in the UK, I have always been taught both orally and written as amps and then I was taught later that amp meant ampere.
+4
Level 74
Jun 3, 2015
I'm curious; what is a steradian used to measure?
+4
Level 35
Jul 24, 2015
I'm not sure but i hope a weber has something to do with grilling.
+6
Level 63
Sep 1, 2016
Solid angles
+2
Level 59
Mar 20, 2022
Solid angle. Basically, a 2d version of angle. For example, you might see it used to measure the apparent sizes of objects in the night sky.
+8
Level 51
Oct 21, 2016
Accept 'mili' for 'milli'?
+3
Level 75
Oct 21, 2016
Surely the base unit should be the gram and the kilogram should be the derived unit.

Otherwise they should have called the kg the gram, the gram the milligram, etc

+12
Level 56
Oct 21, 2016
Nope, the quiz is right. It's confusing, I know. The way this happened is even more confusing and convoluted.
+3
Level 75
Jan 20, 2017
I'm sure it is right, I just meant it seems odd that they worded it that way
+2
Level 38
Jan 20, 2017
If you make the trip you can go and see The Kilogram(IPK) on display in France(or at least one of the sister IPKs)
+2
Level 43
Oct 29, 2019
Well, its a set rule in the world. Quizmaster doesnt make it.
+2
Level 25
Oct 29, 2021
Five years late, but to my knowledge the kg is used as the standard unit as it fits better with the other units (at least in physics). For example, we measure a Newton as 1 kg*m/s^2. If the gram was used instead, we would be dealing with everyday forces in thousands... If we used grams, the force of gravity acting on a 1 kilogram object would be 9,800 N. A 70 kilogram person would be measured as 70,000 grams. It makes calculations far easier and you end up with measurements on a smaller scale that are easier to comprehend. I believe it was called the kg and not the g due to chemistry and the smaller masses involved.
+5
Level 69
Feb 1, 2017
There's a c in Becquerel! Argh! Then I started doubting myself and tried Bechemel instead
+3
Level 49
Dec 3, 2019
lol it would be bechAmel anyways
+4
Level 59
Oct 28, 2021
However you write it, it's surely a lot more tasty
+9
Level 54
Feb 26, 2017
Definitely not a quiz in my wheel house as I thought SI was Sports Illustrated.
+2
Level 75
Jun 24, 2017
Kilogram is scheduled for not being a basic unit anymore. It will be a derived unit from Plank's constant and the Second (thud the speed of light and the meter).

You will be taking weight and time measurements with a tricorder soon.

+13
Level 85
Sep 20, 2017
Atto? Zepto? Yocto? Aren't these Marx brothers?
+1
Level 65
Nov 8, 2017
I was going to post that. You beat me to it!
+1
Level 32
Dec 5, 2017
And I learned yocto before any of the other ones below millionths...
+1
Level 32
Dec 5, 2017
And you can do something like, oh a gigameter
+2
Level 31
Jun 15, 2022
A yoctosecond is a septillionth of a second
+1
Level 71
Dec 9, 2017
Why doesn't mu work for µ? That's what it stands for in physics.
+9
Level 62
Dec 22, 2017
That's the actual Greek letter and it isn't a Prefix I think.
+2
Level 50
Oct 28, 2021
When µ is used with units, it's the "micro" prefix and it means "a millionth"

1 µm is "one micrometer" and it is "a millionth of a meter"

+1
Level 70
May 14, 2024
mumeter sounds fun(ny) though
+1
Level 61
Dec 16, 2017

Tell me if i am wrong(i am not the smartest here;)

+4
Level 70
Aug 17, 2018
No, radians are used to measure angles. There are π radians in 180°, so one radian equates to 180°/π = approx. 57.3°.
+2
Level 37
Jul 19, 2018
Can you please accept deka for deca?
+1
Level 78
Oct 25, 2018
And can you accept Herz for Hertz? My spelling's not too great.
+7
Level 59
Oct 28, 2021
That would be a cardial sin!

(for non-german-speakers: Herz is the german word for heart)

+1
Level 70
Dec 11, 2018
Never heard of sievert and katal (or most of the outer prefixes except iota and got zeta)

Spend way too much time typing becquerel.. I knew it had the u, tried different amounts of r and l, maybe even tried the c, but not cq.

Actually sievert is starting to come back..there was this cartoon called seabert about a seal stopping bad guys... I think there is a link in my memory there

+1
Level 88
Aug 27, 2019
I loved Seabert as a kid! Whenever things go wrong, he'll always come along, let's hear it for Seabert, hooray!
+1
Level 70
Dec 20, 2018
+1
Level 45
May 30, 2019
+1
Level 47
Jan 24, 2019
You forgot feet
+13
Level 32
Jan 31, 2019
The quizz is called scientific units not units used in ancient times(and USA).
+3
Level 79
May 7, 2019
The imperial system is still widely used in the United Kingdom, as well as in the US, Belize and Burma. It was also widely used throughout the Commonwealth until a few decades ago. So not really ancient.
+6
Level 37
Feb 17, 2021
Yes, it is ancient and useless and unscientific.

But if you want to burn a few hundred million dollars every few years due to unnecessary conversion errors - you do you.

+2
Level 66
Aug 27, 2019
it's "gram" the base unit? Kilogram is prefix + base
+2
Level 69
Aug 27, 2019
I grew up thinking that, too. However, no - weirdly in mass only, the 'kilo' is the base unit.
+1
Level 77
Aug 28, 2019
Well, I wrote kilogram as a whole and was surprised I got two answers out of it. XD
+1
Level 65
Aug 28, 2019
This is one of the fel stupid things in the beauty that is the metric system.
+1
Level 43
Aug 27, 2019
39/49 most of these are used in metrology
+2
Level 65
Aug 28, 2019
Nice quiz but too America-centric.
+5
Level 70
Aug 28, 2019
I think it is too rest-of-the-world-except-America-centric. Where are the yards, feet, fathoms and furlongs for length?
+2
Level 60
Jan 24, 2024
I assumed it was sarcastic.
+7
Level 60
Aug 29, 2019
Americans converting for 5 minutes straight.
+1
Level 20
Oct 30, 2019
Incredible how so many of these units come from the electromagnetics !
+1
Level 91
Mar 25, 2020
I suggest accepting candle for candela.....
+1
Level 56
Jul 3, 2021
A candle is actually an imperial unit form luminosity so I think that might make it slightly untrue of a quiz!
+1
Level 70
Oct 6, 2020
Took me ages to get this right. It's bloomin' hard
+2
Level 72
Oct 21, 2020
I think "mili" should be accepted for "milli", as it is the spelling in most of the languages.
+1
Level 23
Apr 10, 2021
please add deka, because it's like that in many languages. and i got them all with my 2nd try LOL
+1
Level 28
Oct 28, 2021
King henry died drinking chocolate milk...
+2
Level 62
Jan 28, 2022
Isn't it Deka with a K instead of a C
+1
Level 65
Jul 20, 2022
It's definitely with a C in all the languages I've learnt it in.
+2
Level 85
Aug 15, 2022
Deka is the spelling for the Greek number ten in the Latin alphabet, but the prefix is deca.
+3
Level 68
Mar 5, 2022
Why is there a unit named after an American car company?
+1
Level 90
Oct 14, 2022
And why is there another one named after an American car industrialist? :)
+1
Level 34
Mar 26, 2022
missed Katal and Gray (':
+1
Level 57
Jul 30, 2022
Could you accept some other spellings for Coulomb? I kept putting the ou in the other spot and it wasn’t accepted.
+1
Level 56
Aug 22, 2022
Form some reason I thought Milli was spelled Mili. Facepalm.
+1
Level 65
Sep 14, 2022
I got everything except zepto and yocto, but i think thats a reflection of me being a massive nerd who does nothing but look at physics articles and read textbooks
+1
Level 28
Sep 27, 2022
2:40 100%
+1
Level 38
Oct 14, 2022
My chemistry teacher would be disappointed in me. Im taking the class now and did TERRIBLE on this! :(
+1
Level 34
Oct 29, 2022
so uh back in the nineteen-eighties i actually worked with stanford moore. you might hhave heard of him? Nobel prize laureate? He was huge. ANyway i wasnt even talking about him

I actually also worked in fred sanger's lab( you probably know him as laureate FREDERICK SANGER ) and hes not even from the united states.

Anyway, before any of this, i was in school. and i remember using H for enthalpy, not Henry. what does a a henry even measure??????

+3
Level 56
Jan 9, 2023
What
+4
Level 37
Jan 22, 2023
they added Q/quetta , R/ronna , r/ronto , q/quecto as prefixes recently, you should update the quiz
+2
Level 68
Mar 26, 2023
Anyone called Ronna should be prepared for some jokes hurled their way, especially if they're on the heavy side.
+1
Level 68
May 16, 2023
Accept Midi-chlorians?
+1
Level 78
Nov 9, 2023
Massively surprised that no one has pointed out that radians and steradians are not derived units. They are, in fact, just numbers.
+2
Level 53
Nov 26, 2023
+2
Level 71
Dec 3, 2023
Funfact: English king Henry II (read: Henry the second) is the only (well-known) person in history, whose name consists of two SI-units (although Becquerel's first name was Henri, but it is spelled differently).
+4
Level 65
Feb 29, 2024