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

Ошибки в процессе измерения являются распространенной проблемой. Такие ошибки могут быть разделены на две категории: случайные и систематические.
Случайные погрешности являются результатом непоследовательности в процессе измерения или вариаций измеряемой величины. Это приводит к колебаниям, слишком высоким или слишком низким, вокруг истинного значения.
Представьте себе ученого, измеряющего длину дождевого червя с помощью штангенциркуля. Непоследовательность ученого в правильном считывании весов или непрерывное движение тела дождевого червя во время измерения, может привести к неправильным измерениям длины.
Случайной ошибки не избежать, однако ее можно усреднить с помощью повторных попыток.
Систематические ошибки являются результатом постоянной проблемы и приводят к постоянному расхождениям в измерениях. Эти погрешности, как правило, либо слишком велики, либо слишком малы по сравнению с истинным значением. Например, гири, измеряемые с помощью неправильно откалиброванных весов.
Они предсказуемы и в основном связаны с приборами. Однако, в отличие от случайной ошибки, она не может быть усреднена при повторном измерении.

Случайные и систематические ошибки

Учёные всегда делают всё возможное, чтобы записывать измерения с максимальной точностью и правильностью Однако иногда ошибки всё же возникают. Эти ошибки могут быть случайными или систематическими. Случайные ошибки наблюдаются из-за несогласованности или колебания в процессе измерения, или изменений в самой измеряемой величине. Такие ошибки колеблются от большего или меньшего значения относительно истинного значения при повторных измерениях. Представьте себе учёного, измеряющего длину дождевого червя с помощью линейки. Случайной ошибкой в ​​этом процессе измерения может быть непоследовательный метод, которым учёный считывает шкалу, или движение червя. Случайную ошибку нельзя избежать; однако её можно усреднить при повторных попытках.

Систематические ошибки возникают из-за постоянной проблемы и приводят к последовательному расхождению в измерении. Эти ошибки обычно оказываются либо больше, либо меньше относительно истинного значения. Они предсказуемы и в основном обусловлены инструментальными причинами. Например, неправильно откалиброванный весовой баланс может постоянно взвешивать предметы тяжелее их истинной стоимости. В отличие от случайной ошибки, систематические ошибки нельзя усреднить при повторных измерениях.

Этот текст адаптирован из <a href="https://openstax.org/books/chemistry-2e/pages/1-5-measurement-uncertainty-accuracy-and-precision">Openstax, Chemistry 2e, Section 1.5: Measurement Uncertainty, Accuracy, and Precision.</a>

Ученые всегда стараются сделать все возможное, чтобы записывать измерения с максимальной точностью и точностью. Тем не менее, иногда ошибки все же случаются. Эти ошибки могут быть ...

Education

JoVE Core

Physics

Физика

Unit 1

Раздел 1

Units, Dimensions, and Measurements

Единицы, размерности и измерения

KEY TERMS AND CONCEPTS

ОСНОВНЫЕ ТЕРМИНЫ И ПОНЯТИЯ

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...

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Unit Conversion Steps and Real-World Errors

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accuracy and precision

Repeated Measurements in Science

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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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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

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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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Describe and provide examples of how similar investigations conducted in many parts of the world result in the same outcome.

SC.912.N.1.5.

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SC.912.N.1.6

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SC.912.N.1.7

How Measurement Errors Affect Results

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