Ask A Scientist Physics Archive

name         Fred B.
status       educator
age          old

Question -   I seem to remember (most vaguely)a unit of time called a "Jiffy", or "Jiffi", 
or the like. This is not a joke. My memory thinks it was supposedly the time it took light 
to travel one centimeter in a vacuum! I can find no reference anywhere. Any foundation 
here?
Also, I recall some wag colleagues at Lawrence Radiation Laboratory in the early 1960s 
labeling a nanosecond scale as "Light Feet" - works out very close!
-----------------
Fred,

When people tell you, "They will be there in a 'jiffi' or a 'jif'", they are exaggerating, 
unless of course they can move at the speed of light.

A 'jiffi' or 'jiffy' is the time it takes LIGHT to traverse the distance of 1 centimeter 
(33.3 pico seconds = 0.000,000,000,033,300 seconds).  1 light - cm is pretty quick !!

http://home.att.net/~numericana/answer/units.htm#jiffy

Regards,
Darin Wagner
=====================================================
I have not heard of the "Jiff" unit, but it is 3.33x10^-10 sec/cm, which is not 
particularly fundamental it seems to me.
    There is a set of units, called "Planck units" that arise "naturally" out of 
	the quantum mechanics and relativity. All physical constants can be expressed 
	in terms of combinations of: Newton's gravitational constant, G; the speed of 
	light in a vacuum, c; Planck's constant/2pi  = h/2pi = hbar; Boltzman's constant, 
	k; the charge on the electron, e. While of theoretical use, their sizes are 
	generally not useful for laboratory-size measurements:
See http://www.planck.com
 and http://scienceworld.wolfram.com/physics
for more details.
Vince Calder
=====================================================
Hi Fred,

I am working on it.  Your question intrigued me, because I too remember something about a
 "jiffy".  I could not find it in my usual sources but I have a few books and class notes around 
 the house.  I will keep an eye out for it.  If someone gives YOU the definitive  answer, please 
 forward it on to me.  Now, I am in the mood for a good search.

Hopefully I will get back to you later.

Martha Croll
=====================================================\