have you ever wonder "what makes a second...a second?", wayyyy off topic Options

[lubu]

I was driving home one day in my belove celica....a question popped up in my head "what makes a second, a second"??...i know there are atomic clocks that miss a second in like 1 million year but how did we even measure a second in the first place...?

Now, a day consists of 24 hours and 1hr=3600 seconds. But we could have had 12 hours in a day and keep the same duration of a second so the number of seconds would still be 3600..it just takes twice as long to move a second to a second...so how and what instument were used to measure a second??

Imagine a second's duration were 10 times faster than today than one would says "yez..my celica can do 0-60mph in abt 60 seconds.." LOL ...yep thats a minute.

[zachattack15]

Stop thinking.

[x_itchy_b_x]

its just a term for measuring how much time has passed. second minute day year age ect. you musta not had much to think about when this manifested in your head.

[Silver94CelicaOw...]

I'm going to play a game and guess why this thought came into your head while driving your beloved Celica...haha.

I bet it had something to do with somebody asking if your car was fast, then saying something to you along the lines of, "for a car to be fast, its gotta run like a 11 second quarter mile, bro!" to which you may have replied, "that uhhh....all depends on what your definition of a second is..."


Hence why this discussion started.

[Culpable04]

1 second can be calculated by the total movement of the earth. 1 full 360* rotation is 1 day ( 24 hrs ) hrs are made by minutes and minutes by seconds.

the movement of the earth is constant and that's the guide we have to check our timing, so a second is just a small movement of earth I have on my notes somewhere what's the distance ( or degree ) earth turn on each second. if you really wanna know about it let me know and I'll post the full formula and such. be ready for calculus and some great geometry

[phonex98]

what culpable said. Goes like this

We know one day (time that it takes for the sun to 'move' one rotation around the earth)(Yes i know i said sun and move). divide one day into 24 partitions. We get hours. Divide those hours into 60 partitions. We get minutes. Divide those AGAIN.. and BAM.. you get a second So yes. its the distance we see the sun move.. or as culpable said, a specific rotation of the earth!

[BloodyStupidDave...]

1 second can be calculated by the total movement of the earth. 1 full 360* rotation is 1 day ( 24 hrs ) hrs are made by minutes and minutes by seconds.

Of course, historically you are correct (this is known as the ephemeris second - ephemeris meaning that which can be calculated using celestial or astronomic data). However, lubu is on the right track with atomic clocks. We (the human race, the scientific community) have changed our definition of a second a few times over the years. The last time was in 1997.

A second is currently defined as:

The duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. This definition refers to a caesium atom at rest at a temperature of 0 K (absolute zero). The ground state is defined at zero magnetic field. The second thus defined is equivalent to the ephemeris second.

http://en.wikipedia.org/wiki/Atomic_clock
http://en.wikipedia.org/wiki/Ephemeris
http://en.wikipedia.org/wiki/Second

[shin]

i swear man... topics here just gets weirder and weirder everyday

[tomazws]

Are we gonna go into why "second" is CALLED "second", or like how come there are 60 seconds in a minute, but only 24 hours in a day?

[phonex98]

sure ! Why not. This from wikipedia:

Twelve

Base-12 systems (duodecimal or dozenal) have been popular because multiplication and division are easier than in base-10, with addition just as easy. 12 is a useful base because it has many factors. It is the smallest multiple of one through four and of six. We still have a special word for "dozen" and just like there is a word for 102, hundred, there is also a word for 122, gross. Base-12 could have originated from the number of knuckles in the four fingers of a hand excluding the thumb, which is used as a pointer in counting.

There are 24 hours per day, usually counted till 12 until noon (a.m.) and once again until midnight (p.m.), often further divided per 6 hours in counting (for instance in Thailand) or as switches between using terms like 'night', 'morning', 'afternoon', and 'evening', whereas other languages use such terms with durations of 3 to 9 hours often according to switches at some of the 3 hour interval marks.


Sixty

Base 60 (sexagesimal) was used by the Sumerians and their successors in Mesopotamia and survives today in our system of time (hence the division of an hour into 60 minutes and a minute into 60 seconds) and in our system of angular measure (a degree is divided into 60 minutes and a minute is divided into 60 seconds). 60 also has a large number of factors, including the first six counting numbers. Base-60 systems are believed to have originated through the merging of base-10 and base-12 systems.

[playr158]

measurements of cesium FTW

go take a college level physics 2 class and you will learn

This post has been edited by playr158: Jul 16, 2007 - 12:34 PM

[lubu]

g
go take a college level physics 2 class and you will learn

yea i took advanced physics in my engineering course..hehehe but nothing abt this sort of thing. So its the pendulum swing that was used to defined a second..um quite interesting. I thought it was only used to measure the earth's weight...no wonder why we still see the grandfather clock with those pendulums.

[carb0n_f1b3r]

I would suggest sticking to a nominal unit of time or vector as a definition..as velocity increases the duration of the second increases, or the faster you go the slower time goes

heres the wiki
http://en.wikipedia.org/wiki/General_relativity

physics rocks

[playr158]

g
go take a college level physics 2 class and you will learn

yea i took advanced physics in my engineering course..hehehe but nothing abt this sort of thing. So its the pendulum swing that was used to defined a second..um quite interesting. I thought it was only used to measure the earth's weight...no wonder why we still see the grandfather clock with those pendulums.

dude learn how to quote people
pendulum swing has nothing to do with defining a "second" it has to do with the atoms of cesium..

pendulum can be different then a "second" just think metronome

[Culpable04]

I would suggest sticking to a nominal unit of time or vector as a definition..as velocity increases the duration of the second increases, or the faster you go the slower time goes

heres the wiki
http://en.wikipedia.org/wiki/General_relativity

physics rocks

that's deep water, that's basically the 3rd postulate of the relativity theory that Einstein always talked about

being honest it took me a couple hours to actually get the concept of such theory and then it took me a couple days to accept it.

modern physics can get you looking like Einstein in no time.

[BloodyStupidDave...]

Are we gonna go into why "second" is CALLED "second"

Oh, if you insist!

Minute is actually short for prime minute, or "minuta prima" in Latin. Minuta is Latin for division, so prime minute means main, first or important division (of an hour).

Second is short for second minute and means small division (of an hour).

[tomazws]

Are we gonna go into why "second" is CALLED "second"

Oh, if you insist!

Minute is actually short for prime minute, or "minuta prima" in Latin. Minuta is Latin for division, so prime minute means main, first or important division (of an hour).

Second is short for second minute and means small division (of an hour).

This further explains the saying "there are no stupid questions" lol

I have to say I learned something new from this thread.

[lubu]

g
go take a college level physics 2 class and you will learn

yea i took advanced physics in my engineering course..hehehe but nothing abt this sort of thing. So its the pendulum swing that was used to defined a second..um quite interesting. I thought it was only used to measure the earth's weight...no wonder why we still see the grandfather clock with those pendulums.

dude learn how to quote people
pendulum swing has nothing to do with defining a "second" it has to do with the atoms of cesium..

pendulum can be different then a "second" just think metronome

i guess i didnt make it clear. my question should be what instrument were FIRST used to measure a second. From what i read on wiki "The seconds pendulum was proposed as a unit of length as early as 1660 by the Royal Society of London. The duration of a beat or half period (one swing, not back and forth) of a pendulum one metre in length on the earth's surface is approximately one second.[2]
"

This post has been edited by lubu: Jul 16, 2007 - 11:23 PM

[RbrtNdrws]

Why aren't they called "firsts" ? EDIT : I figured it out lol.

This post has been edited by RbrtNdrws: Jul 17, 2007 - 2:01 PM

[ScoobyDooCruiser]

Also, interesting to note why time was divided using the base 60 and 12 number systems (that the wikipedia article didn't answer) is because 360 is close to 365. Thus, early western atronomers (Ptolemy mainly) chose the 360 as easy, hence the 60 base. The great sphere (aka the sky, or heavens) move about 1° a day if you have 360° be a full circle. From this convention of 360 for a full circle, a base 60 system was convenient. Thus... as said above... convention, by means of the base 60 system, determined the second.

So, why is a second a second? Well... because the number 365 is close to 360.