process: measuring measuring things that are impossible to measure

sometimes things are too large

or too small
or too fast
or too slow
or too massive
or too light to measure directly.

scientists employ a variety of creative ways in their quest for elusive information.
One of the most baffling concepts was the speed of light. It's so-o-o-o-o-o fast it seemed impossible to measure
(186,000 miles per second or 300,000 km / second).

like many tales from the history of science -- this measurement was made when someone was trying to measure something else, and by accident realized he had stumbled on a method to measure the speed of light. Actually, two accidents. Eureka !

jan 7th, 1610:
the Italian, Galileo, was using his new toy - the telescope - to observe Jupiter -- when by "accident" he discovered that the huge planet had moons. Interesting.

1675:
65 years later -- the orbital speed of these satellites had been determined thru the processes of observing; measuring & collecting data.

it was the Danish astronomer, Ole Roemer, who was "showing off" his knowledge of Jupiter's moons in 1675 when, much to his embarrassment, he screwed up.
He knew ( from 65 years of data -- 1675 - 1610 = 65 yrs ) at precisely what moment a moon ( Io ) would disappear behind or in front of the planet and be eclipsed. "Watch," he would say ( in Danish, of course ) . . . "the eclipse will occur in 5-4-3-2-1 -- Now !"

And guess what ? IT DID.
Sometimes.

other times his prediction ( another process ) wasn't even close -- it was -- gasp, gasp -- 16+ minutes late ! About 1,000 seconds !

now what ?
Sketch of diagram of the sun / earth / jupiter / Io. Show earth orbiting the sun -- and jupiter in its orbit -- farther away. Going around jupiter will be Io ( pronounced: eeeee-oh )
Sometimes the eclipse prediciton was on time --- and other times it was up to 1,000 seconds late. Hmmm. Critical thinking, anyone ?
The speed of light is 186,000 miles per second. "Prove it !"

refer to other methods to determine the speed of light:
mechanical methods = Fizeau ( 1849 ); Foucault ( 1850 ); Michelson ( l878 + 50 yrs ).
Was that Foucault guy the same one who proved earth spun on its axis in 1850 ? Busy guy --- the Foucault Pendulum.

measuring the impossible

here are some other things that might seem to be impossible to measure, but make a list of the processes by which you can determine the . . .

volume of a drop of water
mass of a grain of rice
width of a human hair
volume of an egg
thickness of a sheet of paper

list the limitations for each method.

would an overhead projector help with any of them?

3 / 11f / 94 - 12 / 16s / 95