Science Corner!

On this edition of Science Corner, we are going to explore the female orgasm. But since that doesn't exist, we'll look at standards of the metric system.

There's a long history of trying to find a good standard of measurement in the metric system. It may seem academic to be so finicky with the length of a meter or the mass of a kilogram but it makes a big difference when you're sending satellite signals tens of thousands of meters into space, shipping 20,000 kilograms of bananas or machining parts for spy cameras that can fit inside a pair of eyeglasses. Originally, an important reason for creating the metric system arose from the differently sized units across Europe. The pound of the Saxon king's tax collector might differ from the french merchants travelling through their land and this caused many disputes in Europe at the end of the 18th century. After the French Revolution of 1789, France adopted the metric system and it slowly spread across the world (so slowly in fact that it still hasn't reached the bumpkins in the recently discovered New World). Now, the hard part: creating standards for the basic units of measurement.

We must start with the second because the measurement of the meter depends on it. The original definition was 1/86,400 of the average solar day. Always looking for more precision and relation to widely measured phenomena, it's now defined as 9,192,631,770 periods of vibration of the radiation emitted by cesium-133 at a certain wavelength and at a temperature of absolute zero.

And now with the second safely accurate, we can move onto the meter. The definition of the meter began as 1/40,000,000th of the circumference of the earth. And how did they determine the circumference of the earth? A good question. The French government sent out several teams to measure the longest stretch of meridian they could find over land. Luckily, they chose the meridian passing from Dunkirk to Barcelona that mostly goes over French territory. During the long process of measurement, war broke out between Spain and France (reading history gets depressing, I have no idea why this war started but I'm sure the people (or at least the governments) of that time thought they had a just and noble cause, it makes it so clear that history just repeats itself and nothing that's occurred in the last hundred years, no matter how important it seems to us, will matter in a few centuries). However, the Spaniards thought the process of measurement so important that they had their soldiers escort the french team through their territory. Once they finally measured the circumference of the Earth, they made a platinum-iridium alloy bar (which resists changes in shape) and stored it in a vault in France. They only brought out this treasure once a year to make new copies for use around the world. As the Industrial Revolution increased the need for precision and measurements of the Earth became more accurate, the weakness of this system became apparent. It's now defined as the distance travelled by light in 1/299,792,458 second in absolute vacuum (Aren't you glad we defined seconds already).

I'm saving the most interesting unit for last (although some of my faithful readers may declare that to not be much of a horse race). While the other two basic units (and the ampere for electricity), have an accurate definition using natural and repeatable measurements, the definition of a kilogram, originally one millionth the mass of a cubic meter of water, is now just a hunk of platinum-iridium alloy called "Le Grand K" (does that sounds like a perfume from Pepe Le Pew?) . Not a good system. What if something happens to this valuable piece of metal?

Here's some proposals on the table to sex up the kilogram definition from a Wired article on the subject (which prompted this whole post and gave me the material for the last paragraph):

The longest running proposal is to use a watt-balance machine, which measures the exact force required to balance a 1 kilogram mass against the pull of Earth's gravity. The hitch here is getting a suitably accurate measurement of Planck's constant, and that's proving tougher than anticipated.

As profiled in WIRED 15.09, Australian scientists are building an ultrapure silicon ball that should contain 215 x 1023 atoms, and would henceforth be the new definition of one kg.

A Georgia Tech professor proposed that a kilogram be defined as 18 x 14074481^3 carbon-12 atoms, but carbon is apparently a bit out of fashion in the physics community.

Well, I guess all we can do now is wait with bated breath for 2011 when metric system governing body takes a look at a kilogram redefinition.