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

Das internationale Einheitensystem ist auf der ganzen Welt weit verbreitet, und die Basiseinheiten sind Meter, Kilogramm und Sekunden. Diese Einheiten sind absolut, und ihr Wert ändert sich nicht je nach Standort.
Präfixe werden verwendet, um größere und kleinere Mengen zu definieren. Milli, Mikro und Nano werden verwendet, um kleinere Mengen zu bezeichnen, während Kilo, Mega und Giga verwendet werden, um größere Mengen zu bezeichnen.
Unter den Basiseinheiten ist das Kilogramm jedoch die einzige Basiseinheit, die mit einem Präfix definiert ist.
Beim Ausdrücken von Einheiten und Präfixen müssen einige Regeln beachtet werden. Erstens werden Punkte verwendet, um Einheiten in zusammengesetzten Einheiten zu unterscheiden.
Zweitens wird ein Präfix im Nenner vermieden und nur im Zähler der zusammengesetzten Einheit ausgedrückt.
Drittens gilt die Exponentialpotenz einer Einheit mit einem Präfix für das Präfix und seine Einheit, und schließlich wird das Ergebnis mit einem einzigen Präfix dargestellt.
Im Gegensatz zum metrischen System verwendet das SI keine Vielfachen von Deca oder Centi.

<ol>
	<li>Hibbeler, R.C. (2016). Technische Mechanik \u2012 Statik und Dynamik. Hoboken, New Jersey: Pearson Prentice Hall. Seite 9\u201210</li>
	<li>Bier, F.P.; Johnston, E.R.; Mazurek, D.F.; Cromwell, P.J. und Self, B.P. (2019). Vektormechanik für Ingenieure \u2012 Statik und Dynamik. New York: McGraw-Hill. Seiten 5 und 7</li>
	<li>Meriam, J.L.; Kraige, L.G. und Bolton, J.N. (2020). Technische Mechanik \u2012 Statik. Hoboken, New Jersey: John Wiley. S. 7 und 8</li>
</ol>

internationales einheitensystem

Das Internationale Einheitensystem, bekannt als das SI-System, ist ein international anerkanntes Messsystem, das weltweit anerkannt und verwendet wird. Das SI-System basiert auf einer Reihe von drei Basiseinheiten, die als absolut betrachtet werden und deren Werte sich mit dem Standort nicht ändern. Diese Basiseinheiten sind Meter, Kilogramm und Sekunden. Präfixe werden verwendet, um sowohl größere als auch kleinere Mengen im SI-System zu definieren. Zum Beispiel definieren milli, micro und nano kleinere Mengen, während kilo, mega und giga verwendet werden, um größere Mengen zu definieren. Das Kilogramm ist die einzige Basiseinheit, die im SI-System ein Präfix hat. Beim Ausdruck von Einheiten und Präfixen müssen mehrere Regeln beachtet werden. Erstens werden Punkte verwendet, um Einheiten in Verbundeinheiten zu unterteilen. Zweitens wird ein Präfix im Nenner vermieden und nur im Zähler einer Verbundeinheit ausgedrückt. Drittens gilt eine exponentielle Potenz auf einer Einheit mit einem Präfix für das Präfix und die zugehörige Einheit. Schließlich werden Ergebnisse mit einem einzigen Präfix dargestellt. Es ist wichtig zu beachten, dass das SI-System im Gegensatz zum metrischen System keine Vielfachen von deca oder centi verwendet. Die Präfixe des SI-Systems basieren auf Zehnerpotenzen, wobei die Basiseinheit kein Präfix hat. SI-Einheiten sollen wissenschaftliche Messungen vereinfachen und standardisieren, indem sie ein universales System nutzen. Einer der Hauptgründe, warum das SI-System weltweit verwendet wird, ist dessen Genauigkeit und Präzision bei der Messung. Sogar die winzigsten und massivsten Mengen können genau mit ihren Basiseinheiten und Präfixen quantifiziert werden. Die Basiseinheit des SI-Systems für Länge ist der Meter, definiert als die Strecke, die Licht in einem Vakuum während eines bestimmten Zeitraums zurücklegt. Andere Maßeinheiten wie Zentimeter, Kilometer und Millimeter können mit dem Präfixsystem vom Meter abgeleitet werden. Die Basiseinheit des SI-Systems für Masse ist das Kilogramm, definiert als die Masse einer Reihe von grundlegenden Objekten, die als Internationaler Prototyp des Kilogramms bekannt sind. Andere Massenmessungen wie Gramm und Milligramm können mit dem Präfixsystem vom Kilogramm abgeleitet werden. Die Basiseinheit des SI-Systems für Zeit ist die Sekunde, definiert als die Dauer von 9.192.631.770 Schwingungen der Strahlung in Zusammenhang mit einem bestimmten Übergang zwischen Energiegebieten eines Cäsium-133-Atoms. Aus der Sekunde können andere Zeitmessungen wie Minute und Stunde mit dem Präfixsystem abgeleitet werden. Neben diesen Einheiten werden noch vier weitere als fundamentale Einheiten der Messung definiert. Es handelt sich um das Ampere, Kelvin, Mol und Candela.

Internationales Einheitensystem

Das Internationale Einheitensystem, bekannt als SI-System, ist ein allgemein anerkanntes und weltweit verwendetes Messsystem. Das SI-System ist ...

Education

Lehre

JoVE Core

Mechanical Engineering

Maschinenbau

Unit 1

Einheit 1

An Introduction to Statics

Einführung in die Statik

KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

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

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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...

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

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Physics

PHYS.1

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Chemistry and Physics

IPC.1

IPC.1.E

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112.51.c.1.A.

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112.51.c.1.B.

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112.51.c.1.C.

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112.51.c.1.D.

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112.51.c.1.F.

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112.51.c.1.G.

Scientific Laws and Theories

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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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112.51.c.2.B.

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SI Units and Metric Prefixes

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