## PSN-L Email List Message

From: ChrisAtUpw@.......
Date: Mon, 10 Apr 2006 11:24:17 EDT

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In a message dated 10/04/2006, ian@........... writes:

When we  buy a quantity of goods, like flour for instance, we put the flour
on a  weighing machine, which measures the weight but, under the metric system,
we  quote the weight in units of mass (Kg).

Now if we buy 10 Kg of  flour in Reykjavik then take it and the measuring
machine to Panama and  measure out another 10 Kg, we will find that the two 10 Kg
bags of flour are  different (by a tiny amount).

Hi Ian,

Only if you use a force balance. If you use balance  scales with weights,
or a steelyard, you get no variation, because they measure  mass.

Regards,

Chris Chapman

In a message dated 10/04/2006, ian@........... writes:
<=
FONT=20
style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size=
=3D2>When we=20
buy a quantity of goods, like flour for instance, we put the flour on a=20
weighing machine, which measures the weight but, under the metric system,=20=
we=20
quote the weight in units of mass (Kg).  Now if we buy 10 Kg=20=
of=20
flour in Reykjavik then take it and the measuring machine to Panama and=20
measure out another 10 Kg, we will find that the two 10 Kg bags of flour a=
re=20
different (by a tiny amount).

Hi Ian,

Only if you use a force balance. If you use bal=
ance=20
scales with weights, or a steelyard, you get no variation, because they meas=
ure=20
mass.

Regards,

Chris Chapman
```