Standard Masses, 1A10.20

Topic and Concept:

• Measurement, [:Measurement: 1A10. Basic Units]

Location:

• Cabinet: [:MechanicsCabinet:Mechanic (ME)]

• Bay: [:MechanicsCabinetBayA3:(A3)]

• Shelf: #1

attachment:BasicUnits-03-400.jpg

Abstract:

Show students a 1 lb mass and a 1 kg mass.

Important Setup Notes:

• N/A

Setup and Procedure:

1. Set out the above equipment.
2. Compare the 1 lb mass to a 1 kg mass, by placing the one pound mass on a balance with the equivalent mass in grams on the other side.

Cautions, Warnings, or Safety Concerns:

• N/A

Discussion:

A 1 lb mass and a 1 kg mass is set out for the students to compare. One can use a double pan balance to compare there mass.

The SI unit of mass, the kilogram, is defined as the mass of a specific platinum iridium alloy cylinder kept at the International Bureau of Weights and Measures at Sevres, France. This mass standard was established in 1901, and there has been no change since that time because platinum iridium is an unusually stable alloy. The Sevres cylinder is 3.9 centimeters in diameter and 3.9 centimeters in height. A duplicate is kept at the National Bureau of Standards in Gaithersburg, Md.

Videos:

• [https://www.youtube.com/user/LectureDemostrations/videos?view=1 Lecture Demonstration's Youtube Channel]

References:

• [http://www.nist.gov/index.html National Institute of Standards and Technology's web site]

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