Name: si units and metric prefixes
Uploaded: 2023-09-22T11:49:19.000Z
Duration: 1 min 29 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Specialised Topic in Science

112.51.c.1.

112.51.c.1.E.

International System of Units

Le système international d’unités est largement accepté dans le monde entier, et les unités de base sont les mètres, les kilogrammes et les secondes. Ces unités sont absolues et leur valeur ne change pas en fonction de l’emplacement.
Les préfixes sont utilisés pour définir des quantités plus grandes et plus petites. Milli, micro et nano sont utilisés pour désigner de plus petites quantités, tandis que kilo, méga et giga sont utilisés pour désigner de plus grandes quantités.
Cependant, parmi les unités de base, le kilogramme est la seule unité de base définie par un préfixe.
Quelques règles doivent être suivies lors de l’expression des unités et des préfixes. Tout d’abord, les points sont utilisés pour différencier les unités en unités composées.
Deuxièmement, un préfixe est évité dans le dénominateur et n’est exprimé qu’au numérateur de l’unité composée.
Troisièmement, la puissance exponentielle sur une unité avec un préfixe s’applique au préfixe et à son unité, et enfin, le résultat est représenté à l’aide d’un seul préfixe.
Contrairement au système métrique, le SI n’utilise pas de multiples de déca ou de centi.

<ol>
	<li>Hibbeler, R.C. (2016). Génie mécanique \u2012 Statique et dynamique. Hoboken, New Jersey : Pearson Prentice Hall. pp 9-10</li>
	<li>Bière, F.P. ; Johnston, E.R. ; Mazurek, D.F ; Cromwell, P.J. et Self, B.P. (2019). Mécanique vectorielle pour les ingénieurs \u2012 Statique et dynamique. New York : McGraw-Hill. pages 5 et 7</li>
	<li>Meriam, J.L. ; Kraige, L.G. et Bolton, J.N. (2020). Génie mécanique \u2012 Statique. Hoboken, New Jersey : John Wiley. pages 7 et 8</li>
</ol>

système international d'unités

Le Système international d'unités, connu sous le nom de système SI, est un système de mesure universellement accepté, reconnu et utilisé dans le monde entier. Le système SI est basé sur un ensemble de trois unités de base considérées comme absolues, et leurs valeurs ne changent pas en fonction de la localisation. Ces unités de base sont le mètre, le kilogramme et la seconde. Des préfixes sont utilisés pour définir à la fois des quantités plus grandes et des quantités plus petites dans le système SI. Par exemple, milli, micro et nano définissent des quantités plus petites, tandis que kilo, méga et giga sont utilisés pour définir des quantités plus grandes. Le kilogramme est la seule unité de base définie avec un préfixe parmi les unités de base du système SI. Plusieurs règles doivent être respectées lors de l'expression des unités et des préfixes. Premièrement, des points sont utilisés pour différencier les unités en unités composites. Deuxièmement, un préfixe est évité dans le dénominateur et n'est exprimé que dans le numérateur d'une unité composite. Troisièmement, une puissance exponentielle sur une unité avec un préfixe s'applique au préfixe et à son unité. Enfin, les résultats sont représentés à l'aide d'un seul préfixe. Il est essentiel de noter que, contrairement au système métrique, le système SI n’utilise pas de multiples de « déca » ou de « centi ». Les préfixes du système SI sont basés sur des puissances de dix, l'unité de base n'ayant aucun préfixe. Les unités SI sont destinées à simplifier et standardiser les mesures scientifiques en exploitant un système universel. L'une des principales raisons pour lesquelles le système SI est utilisé dans le monde entier est son exactitude et sa précision en matière de mesure. Même les quantités les plus minuscules et les plus massives peuvent être quantifiées avec précision grâce à leur unité de base et à leur préfixe. L'unité de base du système SI en ce qui concerne la longueur est le mètre, défini comme la distance parcourue par la lumière dans le vide pendant un laps de temps spécifique. D'autres mesures, telles que le centimètre, le kilomètre et le millimètre, peuvent être dérivées du mètre à l'aide du système de préfixe. L’unité de base du système SI en termes de masse est le kilogramme, défini comme la quantité de masse d’un ensemble d’objets fondamentaux connu sous le nom de prototype international du kilogramme. D’autres mesures de masse, telles que les grammes et les milligrammes, peuvent être dérivées du kilogramme à l’aide du système de préfixe. L’unité de base du système SI en termes de temps est la seconde, définie comme la durée de 9 192 631 770 cycles de la radiation associée à une transition spécifique entre les niveaux d’énergie d’un atome de césium-133. À partir de la seconde, d’autres mesures de temps, telles qu’une minute et une heure, peuvent être dérivées à l’aide du système de préfixe. En plus de ces unités, quatre autres sont définies comme des unités fondamentales de mesure. Ce sont l'ampère, le Kelvin, la mole et la candela.

Système international d'unités

Le Système international d’unités, connu sous le nom de système SI, est un système de mesure universellement accepté, reconnu et utilisé dans le monde entier. Le système SI est ...

Education

Enseignement

JoVE Core

Mechanical Engineering

Génie mécanique

Unit 1

Unité 1

An Introduction to Statics

Introduction à la statique

KEY TERMS AND CONCEPTS

TERMES ET CONCEPTS CLÉS

si units and metric prefixes

SI units and metric prefixes provide a standard way to measure size, mass, and time. The International System of Units, or SI system, is used worldwide because it gives scientists a common language for measurement. Its values do not change with location, which helps keep results consistent.

The SI system is built on three base units: meter, kilogram, and second. These are the core units for length, mass, and time. The kilogram is the only base unit that already includes a prefix.

Prefixes make it easy to express very large or very small values. Milli, micro, and nano represent smaller quantities. Kilo, mega, and giga represent larger quantities. SI prefixes are based on powers of ten, and the base unit has no prefix.

Several rules apply when writing SI units. Dots are used to separate units in composite units. A prefix should not appear in the denominator, only in the numerator. If a unit with a prefix is raised to a power, the power applies to both the prefix and the unit. The final answer should use just one prefix. Unlike the metric system, SI does not use deca or centi.

SI units help simplify and standardize scientific measurements. They also improve accuracy and precision, even for very small or very large quantities. The meter is defined as the distance light travels in a vacuum during a specific time frame. Other length units, such as centimeter, kilometer, and millimeter, come from the meter.

The kilogram is the SI base unit of mass. It was defined as the mass of a set of foundational objects called the International Prototype of the Kilogram. Grams and milligrams are derived from the kilogram. The second is the SI base unit of time and is defined by 9,192,631,770 cycles of radiation from a specific transition in cesium-133. Minutes and hours can be derived from the second. Four more fundamental units are also part of SI: ampere, Kelvin, mole, and candela.

SI Units and Metric Prefixes

an introduction to mechanics

Mechanics in Physics and Engineering

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basic concept

Fundamental Quantities in Engineering Mechanics

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newton's law of motion

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newton's law of gravitational attraction

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units of measurement

SI and Customary Measurement Systems

Mechanical engineering depends on units of measurement for precise and accurate calculations. These units give engineers a standard way to express and compare physical quantities. They are essential when designing and analyzing machines and mechanical systems. Many historical measurement systems have been used over time. Examples include the Babylonian system, the Roman system, the Egyptian system, the Olympian system, the British system, and the Indus Valley system. Today, the International...

international system of units

SI units and metric prefixes provide a standard way to measure size, mass, and time. The International System of Units, or SI system, is used worldwide because it gives scientists a common language for measurement. Its values do not change with location, which helps keep results consistent. The SI system is built on three base units: meter, kilogram, and second. These are the core units for length, mass, and time. The kilogram is the only base unit that already includes a prefix. Prefixes...

numerical calculations

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accuracy, limits, and approximation

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dimensional analysis

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key terms and concepts

Learn how SI units use meters, kilograms, seconds, and metric prefixes to measure length, mass, and time with accuracy and consistency.

SI Units and Metric Prefixes | JoVE K12

JoVE Core Mechanical Engineering offers concise, easy-to-understand animated videos covering key topics such as equilibrium, forces, truss analysis, and structural mechanics. Explore their real-world applications, and witness these concepts in action through scientist-led experiments.

mechanical engineering

Physics

PHYS.1

PHYS.1.E

Chemistry and Physics

IPC.1

IPC.1.E

The Scientific Method

The scientific method is a detailed, empirical problem-solving process used by biologists and other scientists. This iterative approach involves ...

Inductive Reasoning

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Ask questions and define problems related to specialized topics of study based on observations or information from text, phenomena, models, or investigations;

112.51.c.1.A.

Scientific Method

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Demonstrating the Scientific Method with Tree Branches
ExpandObtain branches containing a few dozen typical leaves from five different local tree species. ...

Observation and Background Research
ExpandNOTE: The first two steps in the scientific process involve studying and observing natural phenomena of ...

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Problem Definition

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Apply science practices related to specialized topics of study to plan and conduct investigations or use engineering practices to design solutions to problems;

112.51.c.1.B.

Proper Personal Protective Equipment

Robert M. Rioux &#38; William A Elliott, Pennsylvania State University, University Park, PA
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Emergency Eyewash and Shower Stations

Robert M. Rioux, Pennsylvania State University, University Park, PA
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Electrical Safety

Robert M. Rioux &amp; Suprita Jharimune, Pennsylvania State University, University Park, PA
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Working with Centrifuges

Source: Robert M. Rioux &amp; Suprita Jharimune, Pennsylvania State University, University Park, PA
Earth's gravitational force is capable of separating ...

Working with Hot and Cold Sources

Source: Robert M. Rioux &amp; Suprita Jharimune, Pennsylvania State University, University Park, PA
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Robert M. Rioux &amp; Zhifeng Chen, Pennsylvania State University, University Park, PA
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Chemical Storage: Categories, Hazards And Compatibilities

Source: Robert M. Rioux &amp; Taslima A. Zaman, Pennsylvania State University, University Park, PA
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Safe Handling of Mineral Acids

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Handling Chemical Spills

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Proper Use of Autoclaves

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Fume Hoods and Laminar Flow Cabinets

Robert M. Rioux &amp; William A. Elliott, Pennsylvania State University, University Park, PA
Fume hoods and laminar flow cabinets are engineering controls ...

Decontamination for Laboratory Biosafety

Robert M. Rioux and Zhifeng Chen, Pennsylvania State University, University Park, PA
Decontamination is essential for laboratory biosafety, as the ...

Proper Waste Disposal

Robert M. Rioux and Taslima A. Zaman, Pennsylvania State University, Pennsylvania, PA

Users are responsible for the proper disposal of the waste ...

Use appropriate safety equipment and practices during laboratory, classroom, and field investigations as outlined in Texas Education Agency-approved safety standards;

112.51.c.1.C.

Common Lab Glassware and Uses

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Glassware is a regular appearance in the professional ...

Lab Techniques

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	Here we show the laboratory preparation for 10 students ...

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Proper Lab Notebook Keeping

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	Preparation of the LaboratoryExpand
	Here, we show the laboratory preparation ...

Source: Lara Al Hariri and Ahmed Basabrain at the University of Massachusetts Amherst, MA, USA

	Nitration of Methyl BenzoateExpand
	From this lab onward, ...

Use tools appropriate to the specialized topic of study;

112.51.c.1.D.

SI Units: 2019 Redefinition

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The International System of Units, known as the SI system, is a universally accepted measurement system recognized and used worldwide. The SI system is ...

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Measurement: Derived Units

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Collect quantitative data using the International System of Units (SI) or qualitative data as evidence as appropriate to the specialized topic of study;

Review and Preview

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What is a Frequency Distribution

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Ogive Graph

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Histogram

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Relative Frequency Histogram

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Scatter Plot

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Time-Series Graph

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Bar Graph

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Multiple Bar Graph

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Pareto Chart

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Pie Chart

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Organize quantitative or qualitative data using representations appropriate to the specialized topic of study such as scatter plots, line graphs, bar graphs, charts, data tables, diagrams, scientific drawings, and student-prepared models;

112.51.c.1.F.

Modeling and Similitude

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Typical Model Studies

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Develop and use models to represent phenomena, systems, processes, or solutions to problems as appropriate to the specialized topic of study; and

112.51.c.1.G.

Scientific Laws and Theories

Scientific Laws

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Distinguish among scientific hypotheses, theories, and laws as appropriate to the specialized topic of study.

112.51.c.1.H.

Identify advantages and limitations of models such as their size, scale, properties, and materials as appropriate to the specialized topic of study;

112.51.c.2.A.

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Statistical Analysis: Overview

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Realism in Experimentation

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Bias

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Analyze data appropriate to the specialized topic of study by identifying significant statistical features, patterns, sources of error, and limitations;

112.51.c.2.B.

Scientific and engineering practices. The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to explain phenomena or design solutions using appropriate tools and models. The student is expected to:

SI Units and Metric Prefixes

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