# I am used for measurements. What am I? [closed]

I am used for measurements.
My number is lucky.

Oh, and there's a joke about me living with Santa.

What am I?

Hint 1:

I am in the air.

Hint 2:

I used be an element.

Water

Reasoning:

The triple-point of water is used to define the Kelvin Scale, water's pH is 7, which is a lucky number, and water is polar, just like Santa lives in the North Pole with polar bears.

• Nope ;), why did I not use a question mark for my hint? – James Wu May 27 '16 at 0:20
• Water used to define kg, but not anymore. However, water does currently define another SI measurement... (again with the punctuation) – James Wu May 27 '16 at 0:23
• Correct! That's why I was using three points for Hint 3. – James Wu May 27 '16 at 0:26
• Now what about the lucky number or living with Santa? (These might require some chemistry knowledge) – James Wu May 27 '16 at 0:26
• – ev3commander May 27 '16 at 0:28

I think the answer is:

nitrogen

It measures because:

It's lucky because

the atomic number of nitrogen is 7 (lucky)

I haven't figured out the joke yet...

(A possible explanation:)

Santa lives in the North Pole. Nitrogen's symbol is N. "North Pole" contains "N".

it is in the air because earth's atmosphere is 78% nitrogen

• Close! You are on the right track... – James Wu May 23 '16 at 0:45
• Wait so what's wrong? The joke? – ev3commander May 23 '16 at 1:16

7

Used for measurements

as the days of the week

My number is lucky

as in lucky # 7

and there's a joke about me living with Santa

"Seven" ~ "Elven"

• but what is the joke? – manshu May 21 '16 at 20:02
• How is "Seven" ~ "Elven" a joke about living with santa? – 0xcaff May 22 '16 at 4:00
• Not quite... This one might be a little hard then. I'll add a hint. – James Wu May 22 '16 at 20:21
• Wasn't sure about the joke, just that seven would relate to elven. @Chowzen does make the connection in his answer though I'm still not sure about it. – cr0 May 22 '16 at 23:34

Water

Used for measurements

Kelvin is defined as 1/273.16 of the triple point of water.

The old definition of kilogram is the weight of a cubic decimeter of water at 4˚ C. (Confirmed wrong), solids displace water in a graduated cylinder so you can find out volume (Confirmed wrong),water gauge is a measure of pressure (thanks @LiamH)

Lucky

IDK. Possibly because it contains Oxygen (8) which is a lucky number in Chinese (confirmed wrong)

Also:

The molecular mass ~ 18, which is a lucky number in Chinese

Also: (thanks, @Menace)

There are 5 letters in "water", which is a lucky number

Joke

Again, IDK. Possibly because the north pole is covered with water (wrong)

Also (thanks @LiamH again)

something to do with HOH HOH HOH maybe

Hint1

Water vapor is in the air

Hint2

Water is one of the classical elements.

• Correct :), but the measurement, lucky number, and north pole joke were all wrong. I'll accept your answer if you figure out how water fits in (or anyone else who happens to figure it out, though I would give you credit as well). – James Wu May 24 '16 at 21:16
• What about solids displace water in a graduated cylinder so you can find out volume – ev3commander May 24 '16 at 21:20
• Well, your original guess is more accurate... – James Wu May 24 '16 at 21:21
• Oh and waters molecular mass ≈18, which is a lucky number in Chinese. – ev3commander May 24 '16 at 21:25
• @ev3commander water gauge is a measure of pressure. 18 is lucky in Chinese.... and the joke may have something to do with HOH HOH HOH – LiamH May 25 '16 at 13:00

What am I?

Carbon

I am used for measurements.

Carbon-14 is used for measuring the age of fossils.

My number is lucky.

The most common isotope of Carbon is Carbon-12, in which each atom has six protons (which means that Carbon's atomic number is six) and six neutrons.  This is like double sixes or "boxcars" in dice.

Also, 6 is considered a lucky number in China (thanks for the tip, ev3commander).

Oh, and there's a joke about me living with Santa.

Q: Who lives at the North Pole, makes toys and rides around in a pumpkin?
A:  Cinder-"elf"-a!

Carbon is a major component of cinders.

(I may have found the above either here or here.)  Let me go on record as saying that I do not consider this "joke" to be funny.  Maybe people who are younger than seven feel otherwise.

I am in the air.

Wherever there are animals, there is carbon dioxide in the air.

• More on "lucky": 6 is lucky in China – ev3commander May 23 '16 at 10:44
• Thanks! I knew about eight, but I didn't know about 6. – Peregrine Rook May 23 '16 at 15:30

7

It measures

the days of the week

It's lucky because

It's a common lucky number for many people

The joke is

Why does Santa use elves in his workshop? Because the seven dwarves were busy.

• This is the exact same as @cr0's answer. Instead, you should tell them your answer for the joke part. – haykam May 22 '16 at 13:37
• @Peanut It looks like he did tell them... – paste May 22 '16 at 14:02
• Exactly the same, except for the differences. :) – Chowzen May 22 '16 at 23:57

You could be

Krypton

I am used for measurements.

From Wikipedia: In 1960, the International Conference on Weights and Measures defined the meter as 1,650,763.73 wavelengths of light emitted by the krypton-86 isotope.

My number is lucky.

Not sure about this one. The only connection I found is that Krypton's outermost shell has 8 electrons, a lucky number in Chinese numerology.

Oh, and there's a joke about me living with Santa.

Superman, the "Last Son of Krypton" has his fortress of solitude located at the north pole.

Hint 1:

Krypton is a noble gas, and hence in the air

Bonus:

Plus, your avatar is a grumpy looking Batman, who might be sour at Superman, what with their most recent movie.

• Hahaha! I love that bonus explanation. – James Wu May 23 '16 at 14:16

My guess is

Aether

I am used for measurements.

Einstein sometimes used the word aether for the gravitational field within general relativity and this field is used to make many measurements.

My number is lucky.

Again, proceeding with Einstein's interpretation, I think this refers to the Gravitational Constant, $G$. This number is lucky because it is seen as one of the constants that is "fine-tuned" in order for intelligent life to exist within the universe.

Oh, and there's a joke about me living with Santa.

How does Santa travel faster than light?

Because he lives with the Aether Bunny.

Hint 1

The literary definition of aether is: the clear sky; the upper regions of air beyond the clouds.

Hint 2

Aristotle added aether as a fifth element to the classical four of fire, air, water and earth but it's not an element now.

This is an add-on for the correct answer: Could the reasoning for the joke be...

HOH (as stated in the comments for the correct answer, water), has 2 Hs (hence the H^2, hydrogen), and O (as in oxygen). Thus, H^2 and O makes H2O.

• Note quite, but that is pretty smart. – James Wu May 27 '16 at 0:08