### Abstract

It is shown here that five base quantities (and the corresponding five base units) of nature are sufficient to define all derived quantities (and their units) and to describe all natural phenomena. The base quantities (and their base units) are: length (m), mass (kg), time (s), temperature (K) and electric charge (C). The amount of substance (mole) is not taken as a base quantity of nature and the Avogadro constant is not considered as a fundamental constant of nature, as they are both based on an arbitrary definition (due to the arbitrary value of 0.012 kg for the mass of 1 mole of C-12 isotope). Therefore, the amount of substance (mole) is moved from the list of base quantities to the category of the supplementary units (to be re-created after its abrogation in 1995). Based on its definition, the luminous intensity (cd) is not a base quantity (unit), therefore it is moved to the list of derived quantities (units). The ampere and coulomb are exchanged by places in the list of base and derived units, as ampere is a speed of coulombs (but SI defines meter, not its speed as a base unit). The five base quantities are re-defined in this paper by connecting them to five fundamental constants of nature (the most accurately known frequency of the hydrogen atom, the speed of light, the Planck constant, the Boltzmann constant and the elementary charge) with their numerical values fixed in accordance with their CODATA 2006 values (to be improved by further experiments).

Original language | English |
---|---|

Pages (from-to) | 241-246 |

Number of pages | 6 |

Journal | Journal of Mining and Metallurgy, Section B: Metallurgy |

Volume | 47 |

Issue number | 2 |

DOIs | |

Publication status | Published - 2011 |

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### Keywords

- Base quantity
- Base unit
- Fundamental constant
- International system of units
- SI

### ASJC Scopus subject areas

- Metals and Alloys
- Mechanics of Materials
- Materials Chemistry
- Geotechnical Engineering and Engineering Geology

### Cite this

**On the five base quantities of nature and SI (the international system of units).** / Kaptay, G.

Research output: Contribution to journal › Article

}

TY - JOUR

T1 - On the five base quantities of nature and SI (the international system of units)

AU - Kaptay, G.

PY - 2011

Y1 - 2011

N2 - It is shown here that five base quantities (and the corresponding five base units) of nature are sufficient to define all derived quantities (and their units) and to describe all natural phenomena. The base quantities (and their base units) are: length (m), mass (kg), time (s), temperature (K) and electric charge (C). The amount of substance (mole) is not taken as a base quantity of nature and the Avogadro constant is not considered as a fundamental constant of nature, as they are both based on an arbitrary definition (due to the arbitrary value of 0.012 kg for the mass of 1 mole of C-12 isotope). Therefore, the amount of substance (mole) is moved from the list of base quantities to the category of the supplementary units (to be re-created after its abrogation in 1995). Based on its definition, the luminous intensity (cd) is not a base quantity (unit), therefore it is moved to the list of derived quantities (units). The ampere and coulomb are exchanged by places in the list of base and derived units, as ampere is a speed of coulombs (but SI defines meter, not its speed as a base unit). The five base quantities are re-defined in this paper by connecting them to five fundamental constants of nature (the most accurately known frequency of the hydrogen atom, the speed of light, the Planck constant, the Boltzmann constant and the elementary charge) with their numerical values fixed in accordance with their CODATA 2006 values (to be improved by further experiments).

AB - It is shown here that five base quantities (and the corresponding five base units) of nature are sufficient to define all derived quantities (and their units) and to describe all natural phenomena. The base quantities (and their base units) are: length (m), mass (kg), time (s), temperature (K) and electric charge (C). The amount of substance (mole) is not taken as a base quantity of nature and the Avogadro constant is not considered as a fundamental constant of nature, as they are both based on an arbitrary definition (due to the arbitrary value of 0.012 kg for the mass of 1 mole of C-12 isotope). Therefore, the amount of substance (mole) is moved from the list of base quantities to the category of the supplementary units (to be re-created after its abrogation in 1995). Based on its definition, the luminous intensity (cd) is not a base quantity (unit), therefore it is moved to the list of derived quantities (units). The ampere and coulomb are exchanged by places in the list of base and derived units, as ampere is a speed of coulombs (but SI defines meter, not its speed as a base unit). The five base quantities are re-defined in this paper by connecting them to five fundamental constants of nature (the most accurately known frequency of the hydrogen atom, the speed of light, the Planck constant, the Boltzmann constant and the elementary charge) with their numerical values fixed in accordance with their CODATA 2006 values (to be improved by further experiments).

KW - Base quantity

KW - Base unit

KW - Fundamental constant

KW - International system of units

KW - SI

UR - http://www.scopus.com/inward/record.url?scp=83155185463&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=83155185463&partnerID=8YFLogxK

U2 - 10.2298/JMMB110620015K

DO - 10.2298/JMMB110620015K

M3 - Article

VL - 47

SP - 241

EP - 246

JO - Journal of Mining and Metallurgy, Section B: Metallurgy

JF - Journal of Mining and Metallurgy, Section B: Metallurgy

SN - 1450-5339

IS - 2

ER -