Calibrate your finger
Do you know how long your index finger is?
When you don't have a ruler or measuring tape, you can measure lengths, widths, diameters, and thicknesses by using your index finger as a ruler. It's amazingly quick and surprisingly accurate.
Look at your index finger with the palm of your hand open and facing towards you. It turns out that from your index fingertip to the first joint is about one inch.
Measure between the first and second joint, from one crease in the skin, or line, to the next. Again, it's almost exactly one inch. It turns out that the finger is about 3 inches long. But you'll have to measure your
own fingers to find out the precise measurement between
each line on your finger. Discover where the lines on your
finger are exactly at inch intervals.
Why do this? It's extremley 'handy' to know these dimensions
to be able to measure objects when you're in a hurry and you
don't have a tape measure or ruler, for example, while shopping.
You'll find that it's quite easy to estimate to an 1/8th of an inch.
How long would it take for you to find a measuring tape right now?
Before you start looking, using your finger, measure the width of
the ALT key on your keyboard.
I'm looking at it right now and it seems like it would be 3/4".
(Greater than half the distance between the lines, plus half again
as much.) Checking with a tape measure, I was off by a 1/16".
Accuracy to within an 1/16th" is pretty good in most instances,
and more reliable than 'guess'-timating.
It measures 3 1/4" from the tip of my finger to the line at my
knuckle. But since that line isn't perpendicular to the centerline
of the finger, the measurement on the opposite side of the finger
will be shorter. In my case, 2 7/8" long.
Another measurement is from the tip of your index finger to the
next line on your hand between the knuckle and the thumb. I
think palm readers call that your life line.
Now, stretch your pinky and thumb as far apart as possible and
measure that. Mine is 9" give or take an 1/8" depending on how
hard I stretch them. You can put both hands stretched out
like this, thumb tip to thumb tip, and get a measurement
close to 18", hands vary of course. You can hold your index
finger end-to-end with your other hand stretched out and get
something close to 1 foot.
Posted by Muggins