Skip to Main Content
Idaho State University home

Glossary

Filter:
# A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
P
P&D
P3P
PA
PAA
PAD
PAE
PAL
PAP
PAX
PBD
PBX
PC
PCA
PCS
PCZ
PD
Pdl
PDN
PDR
PDS
PDU
PES
PIP
PIX
PKA
PKC
PL
PLA
PM
PMD
PMO
PMP
Pod
POM
Pop
PPL
PPN
PPS
Ps
PSL
PSN
PTR
PTT
PUC
PUT
PVC
PWA
PX
Platinum-Iridium
  • adj. Standard, against which all others of the same category are measured. Usage silly. The notion is that one of whatever it is has actually been cast in platinum-iridium alloy and placed in the vault beside the Standard Kilogram at the International Bureau of Weights and Measures near Paris. (From ~9 to 1960, the meter was defined to be the distance between two scratches in a platinum-iridium bar kept in that same vault --- this replaced an earlier definition as 10^(-7) times the distance between the North Pole and the Equator along a meridian through Paris; unfortunately, this had been based on an inexact value of the circumference of the Earth. From 1960 to 1984 it was defined to be 1650763. 73 wavelengths of the orange-red line of krypton-86 propagating in a vacuum. It is now defined as the length of the path traveled by light in a vacuum in the time interval of 1/299,792,458 of a second. The kilogram is now the only unit of measure officially defined in terms of a unique artifact. ) "This garbage-collection algorithm has been tested against the platinum-iridium cons cell in Paris. " Compare golden.