T Nation

Units of Measurements


So I was getting my nerd on when I came across afew measurements I had never heard of before.

And the measurement was one femtometre. The size roughtly of a Proton/Neutron. Then after reading some more I came across a Yoctometre. If protons and neutrons are the building blocks of everything (the smallest thing we have) what is the measurement "yoctometre" used to measure?

So if anyone can help me out that would be sweet



Oh please don't make me say it.


Protons and neutrons are made up of quarks.


Oh please not a wang joke...

But if someone does know please tell me.


I see. Thats actually cool. I learnt something about science today.


Mildly related is this unit I learned of recently in Richard Dawkin's "The Greatest Show on Earth", called the darwin

darwin: as in 'a darwin'. An eponymous unit of evolutionary change just as a newton is a measure of force, ampere a measure of electrical current and Kelvin a measure of temperature. According to J.B.S. Haldane, one darwin equals a rate of change (for examplein size) of 0.1% per thousand years. Slow chnage would be measured in 'millidarwins', rapid change in 'kilodarwins'. Actually, the darwin has not been much used in the literature to express rates of evolution.

I'll add myself (smart guy that I am) to say that this unit hasn't been used much as I think that different parts of an animal may not change at the same rate as other parts. So they would really need to have a darwin rating for each gene, not for an entire organism.


Neutrinos, apparently.



The smoot is a nonstandard unit of length created as part of an MIT fraternity prank. It is named after Oliver R. Smoot, a fraternity pledge to Lambda Chi Alpha, who in October 1958 lay on the Harvard Bridge (between Boston and Cambridge, Massachusetts), and was used by his fraternity brothers to measure the length of the bridge.


The distance is about 86 Lambda Chi Alpha pledges, give or take a midget.


It is used to measure whatever you are measuring. Orders of magnitude of measurements eg picometre, nanometre etc are just a handy short handed way of saying "1 millionth of a metre" or whatever.

Some measurements are more useful in some situations, but they weren't necessarily "made" in order to measure something.

For example a light year is a huge distance that is often used to describe the distance between stars or galaxies, but it is only used to describe these distances because it is a conveniently huge distance.


The beard-second comes to mind; the length the average physicist's beard grows in one second, established as 5 nanometers.

The barn, shed, and outhouse are also used by physicists "A barn is a serious unit of area used by nuclear physicists to quantify the scattering cross-section of very small particles, such as atomic nuclei.[9] It is one of the very few units which are accepted to be used with SI units, and one of the most recent units to have been established (cf. the knot and the bar, other non-SI units acceptable in limited circumstances).[10] One barn is equal to 1.0x10^-28 m^2. The name derives from the folk expression "Couldn't hit the broad side of a barn", used by particle accelerator physicists to refer to the difficulty of achieving a collision between particles. The outhouse (1.0^10^-6 barns) and shed (1.0x10^-24 barns) are derived by analogy." (from wiki)

As far as I know, the barn is actually the main unit of measurement used by particle physicists working with atom smashers.

And the bridge is actually 364.4 smoots, plus an ear. I've walked over that bridge many times going to MIT.


I hear this man when I read your post.


I understand what you are saying. For example I work in construction and we always use millimetres(mm), well 99% of the time. So I guess when one is talking quantum physics thats when they would use it.


Quantum foam is measured with a yoctometre.


Love "Fringe"!


One thaum is the amount of magic it takes to conjure one white pigeon or three billiard balls.

It is made up of resons, which come in five flavors, up, down, sideways, sex appeal and peppermint.


Hot rodding teenagers from Dimension X?


Fucking avatar WIN.