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

الأخطاء في عملية القياس هي مشكلة شائعة. قد تنقسم هذه الأخطاء إلى فئتين: عشوائية ومنهجية.
الأخطاء العشوائية هي نتيجة عدم الاتساق في عملية القياس أو الاختلافات في الكمية التي يتم قياسها. ينتج عن ذلك تقلبات ، عالية جدا أو منخفضة جدا ، حول القيمة الحقيقية.
ضع في اعتبارك عالما يقيس طول دودة الأرض باستخدام الفرجار. قد يؤدي عدم تناسق العالم في قراءة المقاييس بشكل صحيح ، أو حركة الجسم المستمرة لدودة الأرض أثناء القياس ، إلى قياسات طول غير صحيحة.
لا يمكن تجنب الخطأ العشوائي ، ومع ذلك ، يمكن حساب متوسطه من خلال التجارب المتكررة.
الأخطاء المنهجية هي نتيجة لمشكلة مستمرة وتؤدي إلى تناقض ثابت في القياس. تميل هذه الأخطاء إلى أن تكون إما عالية جدا أو منخفضة جدا مقارنة بالقيمة الحقيقية. على سبيل المثال، يتم قياس الأوزان باستخدام ميزان وزن تمت معايرته بشكل غير صحيح.
هذه يمكن التنبؤ بها ومتعلقة في الغالب بالأدوات. ومع ذلك ، على عكس الخطأ العشوائي ، لا يمكن حساب متوسطه بالقياس المتكرر.

الأخطاء العشوائية والمنهجية

<div style="direction:rtl">يبذل العلماء دائمًا قصارى جهدهم لتسجيل القياسات بأقصى قدر من الدقة والدقة. ومع ذلك، في بعض الأحيان تحدث أخطاء. يمكن أن تكون هذه الأخطاء عشوائية أو منهجية. وتلاحظ أخطاء عشوائية بسبب عدم الاتساق أو التذبذب في عملية القياس، أو الاختلافات في الكمية نفسها التي يتم قياسها. تتقلب مثل هذه الأخطاء من كونها أكبر أو أقل من القيمة الحقيقية في القياسات المتكررة. لنفترض أن عالمًا قام بقياس طول دودة الأرض باستخدام المسطرة. قد يكون الخطأ العشوائي في عملية القياس هذه نتيجة للطريقة غير المتسقة التي يقرأ بها العالم المقاييس، أو إذا كانت دودة الأرض تتحرك. لا يمكن تجنب الخطأ العشوائي؛ ومع ذلك، يمكن حساب متوسطها بالمحاولات المتكررة. تنشأ الأخطاء المنهجية من مشكلة مستمرة وتؤدي إلى تناقض ثابت في القياس. تميل هذه الأخطاء إلى أن تكون دائمًا أكبر من القيمة الحقيقية أو أقل منها. هذه يمكن التنبؤ بها وتكون مفيدة في الغالب بطبيعتها. على سبيل المثال، قد يزن ميزان الوزن الذي تمت معايرته بشكل غير صحيح أشياء أثقل من قيمتها الحقيقية. وعلى عكس الخطأ العشوائي، لا يمكن حساب متوسط الأخطاء النظامية باستخدام القياسات المتكررة. هذا النص مقتبس من <a href="https://openstax.org/books/chemistry-2e/pages/1-5-measurement-uncertainty-accuracy-and-precision">Openstax، الكيمياء 2هـ، القسم 1.5: عدم اليقين في القياس، والدقة، والدقة.</a></div>

يبذل العلماء دائما قصارى جهدهم لتسجيل القياسات بأقصى قدر من الدقة والدقة. ومع ذلك ، تحدث أخطاء في بعض الأحيان. يمكن أن تكون هذه الأخطاء ...

Education

JoVE Core

Physics

الفيزياء

Unit 1

الوحدة الأولى

Units, Dimensions, and Measurements

الوحدات والأبعاد والقياسات

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

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

Estimating Scale with Powers of 10

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models, theories, and laws

Scientific Models, Theories, and Laws

Scientific models, theories, and laws help physicists describe natural phenomena. A model is a simplified version of a physical system that is too complex to study in full. It acts as a rough mental or visual picture of what may be happening. Good models keep the important parts and simplify the rest so the problem becomes workable. The light wave model is one example. Light waves are usually invisible, so they cannot be seen in the same way as water waves. Even so, it is useful to think of...

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units and standards of measurement

SI Units for Physical Quantities

SI units give a standard way to measure physical quantities. A physical quantity can be defined by how it is measured or by how it is calculated from other measurements. For example, the mass and dimensions of a metallic cube can be found with a weighing machine and a meter scale. Some quantities are built from others. The volume of a cube is the cube of its side length. The density of the cube is then found by dividing mass by volume. Measurements are written in units, which are standardized...

estimation of the physical quantities

Fermi Estimation for Physical Quantities

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base quantities and derived quantities

SI Base Units Behind Measured Quantities

SI base units are the starting point for measuring physical quantities. In any system of units, some quantities must be defined through direct measurement. These are called base quantities, and their units are base units. Other physical quantities are built from these base values by algebraic combinations. These are called derived quantities, and their units are derived units. For example, area comes from two lengths multiplied together. It is a derived quantity and is written in SI base units...

conversion of units

Unit Conversion Steps and Real-World Errors

Unit conversion lets you change a measurement from one unit to another. It is useful in everyday life, such as when a cookbook gives amounts in liters or ounces and you need cups instead. It also helps when directions use feet or meters, but you want to know the distance in miles. The first step is to list the given unit and the unit you need. The second step is to choose a conversion factor, which is a ratio that shows how many of one unit equal another unit. For example, 1,000 meters equal 1...

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

Dimensional consistency is a key check in physics equations. It means the dimensions on both sides of an equation must match. The idea helps show whether an equation can represent a real physical law. The first rule is simple: expressions on each side of the equal sign must have the same dimensions. That makes sense because you can only add or subtract quantities of the same type. The second rule says that the input to a standard mathematical function, such as a trigonometric function, a...

problem solving: dimensional analysis

Dimensional Checks for Physics Equations

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solving problems in physics

Physics Problem Solving: Strategy to Check

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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.

The Scientific Method

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Scientific Method

The scientific method is used to solve problems and explain phenomena. The development of the scientific method coincided with changes in philosophy ...

Chemistry is an empirical science. Scientists often pose questions to understand the chemistry in everyday life and seek answers to these questions. To ...

Psychology as a Science

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...

Research is what makes the difference between facts and opinions. Facts are observable realities, and opinions are personal judgments, conclusions, or ...

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

Inductive Reasoning

Inductive reasoning is a form of logical thinking that uses related observations to arrive at a general conclusion. It is uncertain and operates in ...

Deductive Reasoning

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Correlation and Causation

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Recognize that the strength or usefulness of a scientific claim is evaluated through scientific argumentation, which depends on  critical and logical thinking, and the active consideration of alternative scientific explanations to explain the data presented.

SC.912.N.1.3

Scientific Laws and Theories

Scientific Laws

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Reliability in Psychology Experiments

Source: Laboratories of Gary Lewandowski, Dave Strohmetz, and Natalie Ciarocco&#8212;Monmouth University

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Scientists always try their best to record measurements with the utmost accuracy and precision. However, sometimes errors do occur. These errors can be ...

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Uncertainty in Measurement: Accuracy and Precision

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Source: Laboratories of Gary Lewandowski, Dave Strohmetz, and Natalie Ciarocco&#8212;Monmouth University

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Data Validation

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Identify sources of information and assess their reliability according to the strict standards of scientific investigation.

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.

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

SC.912.N.1.6

from-theory-to-design-the-role-of-creativity-in-designing-experiments

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Source: Laboratories of Gary Lewandowski, Dave Strohmetz, and Natalie Ciarocco&#8212;Monmouth University

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Recognize the role of creativity in constructing scientific questions, methods and explanations.

SC.912.N.1.7

How Measurement Errors Affect Results

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