for the metric impaired

[Mako Mark]

I have just finished teaching a class to a diver that just could not get his head around the metric system.

I know that there are a couple of divers out there that come from a small country between Mexico and Canada, that could use some help, so here goes with an explanation that I have found useful.

one liter of water weighs one kilogram.

one liter column of water if squeezed to cover one square centimeter would be one meter tall.

the pressure at the bottom of this water column would be 0.1 of an atmosphere.

to heat that liter of water one degree C, would take 1000 calories.

The only thing missing is velocity, and we dont really need this in diving.

simple huh?

Now, if you go t Cambodia where they traditionally use base four... (one, two, three, four, ten, eleven, twelve, thirteen, fourteen twenty....) and try to apply archemedies principle to calculate the amount of air needed to lift and object...weighing.... with ah.....a volume of...
ah forget it.....

 

[simbrooks]

That is just way to simple, i dont see how anyone would use it when you have a system where you have 12 inches in a foot, 3 feet in a yard, where force and mass are dependant on a gravitational constant to differentiate between them, you have to take 33ft of saltwater to make an atmosphere which is 14.7 psi, temperature at freezing is 32F and boiling is 212F, one cubic foot of water weighs ~62-64# - it is so much easier this way, why would anyone change? Just for the sake of diving?

 

[roakey]

Now, if you go t Cambodia where they traditionally use base four... (one, two, three, four, ten, eleven, twelve, thirteen, fourteen twenty....)

one, two, three (no four), ten, eleven, twelve, thirteen, (no fourteen) twenty...

Or did you mean base five?

Roak

 

[simbrooks]

Me thinks i can see an imperial uprising to continue to fight off the dreaded simple metric system..... (that would cause the US to go bankrupt due to retooling etc, blah, blah, blah).

 

[V-Erthal]

remember this is valid for salt water. the values for fresh water change a bit.

 

[pt40fathoms]

remember this is valid for salt water. the values for fresh water change a bit.

Are you sure of this..............

 

[V-Erthal]

Are you sure of this..............

salt water (remember the presence of salt, witch has mass) is more dense than fresh water (without salt) soooooo....

1 liter of salt water does not weght the same as 1 liter of fresh water, witch means that you wil have 2 atm of pressure in a column of 10 meters of salt water (that has more mass than fresh water. it makes a colum of fresh water to achieve 2 atm of pressure bigger than salt water.

 

[Paul Evans]

The sooner the world goes metric the better

However, And this is the truth :11: the quality and understanding of simple maths will disapear, base 12 does have it's problems but base 10 is so easy the understanding of mathermatics drops off a cliff :06:

My maths is fine, but I can't spell

 

[JimC]

Actualy, to get picky:

10.03m for salt water
10.33m for fresh water

Give or take a bit depending on exact composition of you particular salt and fresh water.

While metric is nice and tight, not everything lines up exactly.

 

[V-Erthal]

Actualy, to get picky:

10.03m for salt water
10.33m for fresh water

Give or take a bit depending on exact composition of you particular salt and fresh water.

While metric is nice and tight, not everything lines up exactly.

Thanks Jim,
I was starting to believe i was wrong...