when your getting smaller in time what are the names of the increments
second milli second etc
Using standard metric notation, it would be second, decisecond, centisecond, millisecond, etc. but I’ve never heard anyone say decisecond or centisecond
Same as with anything else in SI units-
Milli- 10[sup]-3[/sup]= 1/1000th
Micro- 10[sup]-6[/sup]= 1 millionth
Nano- 10[sup]-9[/sup]= 1 billionth
Then Pico, Femto for every extra three zeroes.
So you could call it 10 milliseconds or 1 one-hundredth of a second if you chose, or go straight into scientific notation.
A hunderth of a sceond could be called a centisecond I suppose, but noone uses that. Generally you are going to use 10 ^ 3x where x is an integer.
10 ^ -3 milisecond
10 ^ -6 microsecond
10 ^ -9 nanosecond
10 ^ -12 picosecond
etc
(looks like I was slow in posing)
Brian
We used to have a “centisecond timer” in our physics lab - just a giant stopwatch with a big hand that made one sweep in two seconds IIRC, though how you’d get 10ms accuracy with a hand-operated clock is a mystery to me.
pico, femto, atto are the prefixes down to 10[sup]-18[/sup].
An informal unit of time is the “shake” equal to 1x10[sup]-8[/sup] seconds. Here’s a link http://www.unc.edu/~rowlett/units/dictS.html
(scroll about a third of the way down the page).
A quick Google search turns up about 2,500 online references to centi-second or centisecond.
And it’s fairly common in Mainframe computers, where the statement ACCEPT FROM TIME gives you the current time in the format HHMMSSCC, where the CC indicates centi-seconds.
A “jiffy” is often used to represent small units of time. The problem is it’s not consistant. Sometimes it is used as a nanosecond, sometimes it is used as 1/60th of a second, or sometimes in computers it is whatever frequency the system clock runs at.
A “tick” is often also used in computers, and is usually the base time unit that the time slicing algorithms use. In other words, if the task scheduler runs 100 times per second, then one tick is 1/100th of a second.
Millisecond, microsecond, and nanosecond are all very commonly used by engineers, so much so that “us” is commonly used as an abbreviation for microsecond, since a greek micro isn’t available on most keyboards and looks kind of like a u anyway.
I have heard that Admiral Grace Hopper, one of the pioneers of computer science (she’s often credited with inventing the word “bug” for a computer malfunction, from when a moth flew into a relay in an early computer) used to carry around a piece of wire about a foot long. When people would ask what that was, she would say “a nanosecond.” She would then explain that the speed of light is about a foot per nanosecond, so that piece of wire was how far electronic signals could travel in a nanosecond.
I hadn’t heard that Grace Hopper anecdote before, engineer_comp_geek, but it’s certainly supported by a Web search, which turns up such pages as this.
It raises an interesting question, however: why on earth would she choose a foot-long piece of wire? Although light travels about one foot per nanosecond in a vacuum or in air (as anyone who has worked with pulsed lasers in the picosecond or nanosecond domain can attest, since one can make useful delays by moving mirrors a few millimeters or inches as appropriate), it is down to about 66% of this velocity in metallic (e.g. copper) wires. Thus a “nanosecond” of copper wire is about 8 inches. Although the exact delay depends on several parameters (exact material composition, geometry, resistance, capacitance, inductance, etc), it is much closer to 8"/ns than 1ft/ns in any wire with which I am familiar.
No, it’s called a hundredth of a second.
Having linked to the above page, I should also point out a serious error in it: it states that 12 inches is “the distance an electron moves in one nanosecond”. In a regular metallic wire, the electrical signal moves at the velocity of light in the relevant medium, but the individual electrons move at velocities that are several orders of magnitude lower.
Allow me to point out the serious error in your own post:
Light doesn’t travel in copper wires.
The electromagnetic field propagates (i.e., the light travels) through the dielectric material separating the wires. If that material is a vacuum, the propagation velocity will be c. If the material is, say, polyethylene, like in a polyethylene insulated coaxial cable, the propagation velocity will equal the speed on light in polyethylene, which is about 66% c.
If you have a mixed medium, like a couple of PVC insulated wires surrounded by air, the propagation velocity will depend on the relative thicknesses of the two insulating materials. If the PVC is thin compared to the distance of air, the propagation velocity will approach the volocity of light in air, which is almost c.
If Grace was carrying uninsulated wire, and it looks from the photo that she was, then she was right and you are wrong.
This is a full list of SI prefixes:
yotta- (Y) 10[sup]24[/sup]
zetta- (Z) 10[sup]21[/sup]
exa- (E) 10[sup]18[/sup]
peta- § 10[sup]15[/sup]
tera- (T) 10[sup]12[/sup]
giga- (G) 10[sup]9[/sup]
mega- (M) 10[sup]6[/sup]
kilo- (k) 10[sup]3[/sup]
hecto- (h) 10[sup]2[/sup]
deca- (da) 10
deci- (d) 10[sup]-1[/sup]
centi- © 10[sup]-2[/sup]
milli- (m) 10[sup]-3[/sup]
micro- (μ) 10[sup]-6[/sup]
nano- (n) 10[sup]-6[/sup]
pico- § 10[sup]-12[/sup]
atto- (a) 10[sup]-18[/sup]
zepto- (z) 10[sup]-21[/sup]
yocto- (y) 10[sup]-24[/sup]
This part is screwed up. It should be:
deci- (d) 10[sup]-1[/sup]
centi- © 10[sup]-2[/sup]
milli- (m) 10[sup]-3[/sup]
micro- (μ) 10[sup]-6[/sup]
nano- (n) 10[sup]-9[/sup]
pico- § 10[sup]-12[/sup]
femto- (f) 10[sup]-15[/sup]
atto- (a) 10[sup]-18[/sup]
zepto- (z) 10[sup]-21[/sup]
yocto- (y) 10[sup]-24[/sup]
Haj
Gah! Except for the mu part.
Yes, you’re corrcet I missed ‘femto-’ from my list
engineer_comp_geek: The term `bug’ to describe defect or noise was established by Edison’s time in the engineering trade. Telegraph operators used it to describe the cause of noise in the lines. So it wasn’t invented for computers due to Hopper’s find.
Nor was Hopper the first to apply it to computers. In fact, her logbook contained this entry:
The itaicized section demonstrates that computer operators and technicians had been using the term bug in the earlier sense in reference to computer defects, and that the hapless moth was the first actual bug to ever be found.