# An Introduction to the New SI

```@article{Knotts2015AnIT,
title={An Introduction to the New SI},
author={S M Knotts and Peter J. Mohr and William D. Phillips},
journal={The Physics Teacher},
year={2015},
volume={55},
pages={16-21}
}```
• Published 11 March 2015
• Education, Physics
• The Physics Teacher
Plans are under way to redefine the International System of Units (SI) around 2018. The new SI specifies the values of certain physical constants to define units. This article explains the new SI in order to provide a resource for high school teachers as well as for advanced students already familiar with the pre-2018 SI.
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## References

SHOWING 1-10 OF 16 REFERENCES

### Towards a new SI: a review of progress made since 2011

• Physics
• 2014
In 2011, the General Conference on Weights and Measures (CGPM) confirmed its intention to adopt new definitions for four of the base units of the SI based on fixed numerical values of selected

### About the International System of Units (SI) Part I. Introduction and Bibliography

• Education, Physics
• 2011
Since much of SI is based on physics and mathematics, physics teachers have the background to teach SI. We present this review and summary in a series of SI notes in order to help teachers answer

### Adapting the International System of Units to the twenty-first century

• Physics
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences
• 2011
The objective of the proposed changes is to adopt definitions referenced to constants of nature, taken in the widest sense, so that the definitions may be based on what are believed to be true invariants.

### Defining units in the quantum based SI

Possible changes to the International System of Units (SI) are being discussed, including a proposal to define the units by specifying the values of a set of fundamental constants. This note is an

### A LEGO Watt balance: An apparatus to determine a mass based on the new SI

• Education, Physics
• 2014
The design, construction, and performance of the LEGO watt balance and its ability to determine h, the Planck constant, are presented.

### Resource Letter FC-1: The physics of fundamental constants

• Education, Physics
• 2010
This Resource Letter provides a guide to the literature on the physics of fundamental constants and their values as determined within the International System of Units (SI). Journal articles, books,

### CODATA recommended values of the fundamental constants

• Chemistry
• 2001
A review is given of the latest Committee on Data for Science and Technology (CODATA) adjustment of the values of the fundamental constants, referred to as the 1998 values, which replaces the values recommended for international use by CODATA in 1986.

### A more fundamental International System of Units

The universally accepted method of expressing physical measurements for world commerce, industry, and science is about to get a facelift, thanks to our improved knowledge of fundamental constants.

### A simple watt balance for the absolute determination of mass

• Physics, Education
• 2013
A watt balance is an electromechanical device that allows a mass to be determined in terms of measurable electrical and mechanical quantities, themselves traceable to the fundamental constants of