Name: how measurement errors affect results
Uploaded: 2023-04-30T12:12:04.000Z
Duration: 1 min 20 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Nature of Science

SC.912.N.1

SC.912.N.1.4

Random and Systematic Errors

Fehler im Messprozess sind ein häufiges Problem. Solche Fehler können in zwei Kategorien eingeteilt werden: Zufällig und Systematisch.
Zufällige Fehler sind das Ergebnis von Inkonsistenzen im Messprozess oder Schwankungen in der zu messenden Menge. Dies führt zu zu hohen oder zu niedrigen Schwankungen um den wahren Wert.
Stellen Sie sich einen Wissenschaftler vor, der die Länge eines Regenwurms mit einem Messschieber misst. Die Inkonsistenz des Wissenschaftlers, die Waage korrekt abzulesen, oder die kontinuierliche Körperbewegung des Regenwurms während der Messung kann zu falschen Längenmessungen führen.
Zufällige Fehler lassen sich nicht vermeiden, aber sie können durch wiederholte Versuche ausgeglichen werden.
Systematische Fehler sind das Ergebnis eines anhaltenden Problems und führen zu einer ständigen Diskrepanz bei der Messung. Diese Fehler sind im Vergleich zum wahren Wert entweder zu hoch oder zu niedrig. Zum Beispiel, wenn Gewichte mit einer falsch kalibrierten Waage gemessen werden.
Diese sind vorhersehbar und meist instrumentenbezogen. Im Gegensatz zum Zufallsfehler kann er jedoch nicht durch wiederholte Messung gemittelt werden.

zufällige und systematische fehler

Wissenschaftler versuchen immer ihr Bestes, um Messungen mit größtmöglicher Genauigkeit und Präzision aufzuzeichnen. Allerdings können manchmal Fehler auftreten. Diese Fehler können zufällig oder systematisch sein. Zufällige Fehler werden aufgrund von Inkonsistenz oder Schwankungen im Messprozess oder Variationen in der gemessenen Größe selbst beobachtet. Solche Fehler schwanken bei wiederholten Messungen entweder über oder unter dem wahren Wert. Betrachten wir einen Wissenschaftler, der die Länge eines Regenwurms mit einem Lineal misst. Zufälliger Fehler bei diesem Messprozess könnte das Ergebnis der inkonsistenten Methode sein, mit der der Wissenschaftler die Skalen abliest, oder wenn sich der Regenwurm bewegt. Zufällige Fehler können nicht vermieden werden, können aber mit wiederholten Versuchen ausgeglichen werden.

Systematische Fehler entstehen aus einem fortlaufenden Problem und führen zu einer konsistenten Abweichung in der Messung. Diese Fehler tendieren dazu, entweder größer oder kleiner als der wahre Wert zu sein. Sie sind vorhersehbar und meistens instrumentell bedingt. Zum Beispiel kann eine falsch kalibrierte Waage Objekte immer schwerer wiegen als ihren wahren Wert. Im Gegensatz zu zufälligen Fehlern können systematische Fehler durch wiederholte Messungen nicht ausgeglichen werden.

Dieser Text wurde angepasst von <a href="https://openstax.org/books/chemistry-2e/pages/1-5-measurement-uncertainty-accuracy-and-precision">Openstax, Chemistry 2e, Abschnitt 1.5: Messunsicherheit, Genauigkeit und Präzision.</a>

Zufällige und systematische Fehler

Wissenschaftler versuchen immer ihr Bestes, um Messungen mit höchster Genauigkeit und Präzision aufzuzeichnen. Manchmal treten jedoch Fehler auf. Diese Fehler können ...

Education

Lehre

JoVE Core

Physics

Physik

Unit 1

Einheit 1

Units, Dimensions, and Measurements

Einheiten, Dimensionen und Messungen

KEY TERMS AND CONCEPTS

KERNBEGRIFFE UND KONZEPTE

how measurement errors affect results

Measurement errors can change how accurate and precise a result appears. Scientists try to record measurements as carefully as possible, but errors can still happen. These errors are usually random or systematic.

Random errors come from inconsistency or fluctuation in the measuring process. They can also come from changes in the quantity being measured. In repeated measurements, random error may make a value appear greater than the true value one time and less than it the next.

A simple example is measuring the length of an earthworm with a ruler. The error could come from reading the scale differently each time. It could also happen if the earthworm moves during the measurement. Random error cannot be avoided, but repeated trials can help average it out.

Systematic errors come from a persistent problem that causes a steady measurement shift. They usually make results consistently greater than the true value or consistently less than it. These errors are predictable and are often instrumental in nature.

An improperly calibrated weighing balance is one example of systematic error. It may keep weighing objects heavier than they really are. Unlike random error, systematic error cannot be averaged out by repeating the measurement.

How Measurement Errors Affect Results

the scope of physics

How Physics Shapes Science and Technology

Physics studies the interactions of energy, matter, space, and time. It looks for the basic mechanisms that explain natural phenomena. The word physics comes from the Greek word physis, which means nature. Physics helps us understand the natural world at its most fundamental level. It relies on quantitative laws, or rules written in numbers and measurements, to describe how things behave. That approach can also help other fields improve the limits of current technology. Physics matters in...

orders of magnitude

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models, theories, and laws

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units and standards of measurement

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base quantities and derived quantities

SI Base Units Behind Measured Quantities

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Unit Conversion Steps and Real-World Errors

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accuracy and precision

Repeated Measurements in Science

Repeated measurements help scientists check the quality of their results. They are used to judge both precision and accuracy. These two ideas are related, but they do not mean the same thing. Measurements are precise when repeated trials give very similar results. Precision shows how closely the values agree with one another. Measurements are accurate when the result is very close to the true value or the accepted value. Accuracy shows how closely the values agree with the real target. High...

random and systematic errors

Measurement errors can change how accurate and precise a result appears. Scientists try to record measurements as carefully as possible, but errors can still happen. These errors are usually random or systematic. Random errors come from inconsistency or fluctuation in the measuring process. They can also come from changes in the quantity being measured. In repeated measurements, random error may make a value appear greater than the true value one time and less than it the next. A simple...

rules for significant figures

Measurement Precision and Significant Figures

Measurement precision depends on the tool used, and significant figures show that precision. A ruler can measure length to the closest millimeter. A caliper can measure length to the nearest 0.01 mm, so it gives a more precise measurement because it can detect very small changes in length. When a value is written from a measurement, the last digit is not exact. The person making the measurement must estimate that digit. For example, a stick that seems to fall between 13.2 cm and 13.3 cm must...

significant figures in calculations

Rounding Rules for Significant Figures

Rounding rules for significant figures help show the right level of certainty in measured results. When a calculation is reported with the correct number of significant figures, it better matches the uncertainty in the measurements. The rounding rule depends on the type of math being done. For addition and subtraction, the result should have the same number of decimal places as the number with the fewest decimal places. For multiplication and division, the result should have the same number of...

dimensional analysis

Dimensional Checks in Physics Equations

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problem solving: dimensional analysis

Dimensional Checks for Physics Equations

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key terms and concepts

Learn how random and systematic errors affect scientific measurements, with clear examples like a moving earthworm and an uncalibrated balance.

How Measurement Errors Affect Results | JoVE K12

physics

JoVE Core Physics introduces the theory and application of fundamental physics topics, including kinematics, dynamics, fluid mechanics, statics, waves, and acoustics, with concise and easy-to-understand animated videos. Additionally, the scientist-in-action videos demonstrate the application of related concepts in classical and original research experiments performed in today's laboratories worldwide.

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Define a problem based on a specific  body of knowledge, for example: biology, chemistry, physics, and earth/space science, and do the following:  
Pose questions about the natural world, (Articulate the purpose of the investigation and identify the relevant scientific concepts). 
Conduct systematic observations, (Write procedures that are clear and replicable. Identify observables and examine relationships between test (independent) variable and outcome (dependent) variable. Employ appropriate methods for accurate and consistent observations; conduct and record measurements at appropriate levels of precision. Follow safety guidelines). 
Examine books and other sources of information to see what is already known, 
Review what is known in light of empirical evidence, (Examine whether available empirical evidence can be interpreted in terms of existing knowledge and models, and if not, modify or develop new models). 
Plan investigations, (Design and evaluate a scientific investigation). 
Use tools to gather, analyze, and interpret data (this includes the use of measurement in metric and other systems, and also the generation and interpretation of graphical representations of data, including data tables and graphs), (Collect data or evidence in an organized way. Properly use instruments, equipment, and materials (e.g., scales, probeware, meter sticks, microscopes, computers) including set-up, calibration, technique, maintenance, and storage). 
Pose answers, explanations, or descriptions of events, 
Generate explanations that explicate or describe natural phenomena (inferences), 
Use appropriate evidence and reasoning to justify these explanations to others, 
Communicate results of scientific investigations, and 
Evaluate the merits of the explanations produced by others.

SC.912.N.1.1

Describe and explain what characterizes science and its methods.

SC.912.N.1.2

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SC.912.N.1.3

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SC.912.N.1.5.

Describe how scientific inferences are drawn from scientific observations and provide examples from the content being studied.

SC.912.N.1.6

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SC.912.N.1.7

How Measurement Errors Affect Results

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