The big hand is pointing to I'm and the little hand is pointing to confused

December 12, 2005 6:14 PM

What do these numbers on my watch mean?

I was given a lovely watch as a gift. It is a Michael Kors MK-7000, for those with more googlaptitude than me. The following series of numbers:

60 65 70 75 80 85 90 95 100 105 110 115 120 130 140 150 160 170 180 190 200 220 250 300 350 400 450 500 600 700 1000

is printed counterclockwise around the outer edge of the watch's face. The 60 is above the 12, the 120 below the 6, and the 1000 at approximately 00:04. The spaces between the respective numbers gets progressively smaller from 60-120, gets a bit larger from 120-130 then decreases again to until 250, where it again gets larger and then decreases to 1000.

What gives? Is this just a decorative thing, or am I missing something obvious about this series of numbers? There's nothing in the accompanying booklet offers me any suggestion about what's going on.

posted by hoboynow to Clothing, Beauty, & Fashion (8 answers total)

Best answer: It's a tachymeter.

It's used to figure out your speed, based on either miles or kilometers per minute.
posted by falconred at 6:21 PM on December 12, 2005

Heart Rates? I think if you count a certain number of heart beats, the number the second lands on is the heart rate.

(On preview, falconred might be righter - same principal, but more likely use)
posted by Jimbob at 6:23 PM on December 12, 2005

On not-preview, I feel the need to explain more (sorry folks, brain-dead over here!):

To use the tachymeter, you time how long it takes you to go 1 mile, then compare to the ring around watch face. So if it took you 55 seconds to go a mile, you're going about 65 mph. If it took 15 seconds to go a mile, you're crusing at 240 mph or so.
posted by falconred at 6:26 PM on December 12, 2005

Response by poster: Thanks! That was dead simple.
*goes off and times things*
posted by hoboynow at 6:28 PM on December 12, 2005

I don't know what they mean specifically, but from your description it sounds like the numbers are inversely proportional to the time after the hour. Or, to put it another way, if you do 1000X a minute for (approximately) four minutes, you have done the same number of X as if you did 120X a minute for half an hour, or 60X a minute for an hour. The fact that the spacing between the number decreases as long as the interval between the numbers is constant (as it is between 60 and 120) also supports this.

On preview: looks like falconred is right. The same principle could be used for heart rates, but this particular implementation wouldn't be too practical for human heart rates, as 1000 beats per minute is (probably) unknown, while rates lower than 60bpm are not uncommon.
posted by DevilsAdvocate at 6:28 PM on December 12, 2005

Could this be used to measure data transfer rates? (I suspect it could, and I have to figure these out in my head all the time...)


//big backups, have to predict when they'll be done.
posted by Wild_Eep at 8:22 PM on December 12, 2005

Just for those who might be having a hard time visualizing it, here is a good photo of a watch with a tachymeter.
posted by Plutor at 4:44 AM on December 13, 2005

It doesn't have to be speed or miles per hour or any other specific task. You can use it to measure the rate of any periodic event. Just time how many seconds it takes for one iteration of the event, and the corresponding reading will be the number of times per hour that event will occur.

So, say that you had a dripping sink. You measure the interval between drips to be about 25 seconds. At the 25 second mark on the dial, the tachymeter is just a little up from 140, so you can estimate that there are about 145 drips per hour.
posted by Rhomboid at 10:15 AM on December 13, 2005