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

טעויות בתהליך המדידה הן בעיה נפוצה. שגיאות כאלה עשויות ליפול לשתי קטגוריות: אקראי ושיטתי.
טעויות אקראיות הן תוצאה של חוסר עקביות בתהליך המדידה או שינויים בכמות הנמדדת. אלה גורמים לתנודות, גבוהות מדי או נמוכות מדי, סביב הערך האמיתי.
חשבו על מדען שמודד את אורכה של תולעת אדמה באמצעות קליפר. חוסר עקביות של המדען לקרוא נכון את המאזניים, או תנועת גוף רציפה של תולעת האדמה במהלך המדידה, עלולים לגרום למדידות אורך שגויות.
טעות אקראית לא ניתן להימנע, עם זאת, זה יכול להיות ממוצע עם ניסויים חוזרים.
טעויות שיטתיות הן תוצאה של בעיה מתמשכת ומובילות לפער עקבי במדידה. שגיאות אלה נוטות להיות גבוהות מדי או נמוכות מדי בהשוואה לערך האמיתי. למשל, משקולות שנמדדות באמצעות מאזן שקילה לא מכויל כראוי.
אלה צפויים ובעיקר קשורים למכשירים. עם זאת, בניגוד לטעות אקראית, לא ניתן לחשב אותה במדידה חוזרת.

שגיאות אקראיות ושיטתיות

<div style="direction:rtl">מדענים תמיד מנסים כמיטב יכולתם להקליט מדידות בדיוק ובדיוק מירביים. עם זאת, לפעמים מתרחשות שגיאות. שגיאות אלו יכולות להיות אקראיות או שיטתיות. שגיאות אקראיות נצפות עקב חוסר עקביות או תנודה בתהליך המדידה, או שינויים בכמות עצמה הנמדדת. שגיאות כאלה משתנות מהיותן גדולות או קטנות מהערך האמיתי במדידות חוזרות ונשנות. חשבו על מדען שמודד את אורכה של תולעת אדמה באמצעות סרגל. טעות אקראית בתהליך מדידה זה יכולה להיות תוצאה של השיטה הלא עקבית שבה המדען קורא את המאזניים, או אם תולעת האדמה זזה. לא ניתן להימנע משגיאה אקראית; עם זאת, ניתן לבצע ממוצע של ניסויים חוזרים. שגיאות שיטתיות נובעות מבעיה מתמשכת ומביאות לאי התאמה עקבית במדידה. שגיאות אלו נוטות להיות בעקביות גדולות או קטנות מהערך האמיתי. אלה ניתנים לחיזוי ובאופן אינסטרומנטלי לרוב. לדוגמה, מאזן שקילה מכויל בצורה לא נכונה עלול לשקול באופן עקבי עצמים כבדים יותר מערכם האמיתי. בניגוד לשגיאה אקראית, לא ניתן למצות שגיאות מערכתיות במדידות חוזרות ונשנות. טקסט זה מותאם מ <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></div>

מדענים תמיד מנסים כמיטב יכולתם להקליט מדידות בדיוק ובדיוק מרביים. עם זאת, לפעמים מתרחשות שגיאות. שגיאות אלה יכולות להיות ...

Education

JoVE Core

Physics

פיזיקה

Unit 1

יחידה 1

Units, Dimensions, and Measurements

יחידות, ממדים ומדידות

KEY TERMS AND CONCEPTS

מונחים ומושגים מרכזיים

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

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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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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

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significant figures in calculations

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dimensional analysis

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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

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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). 
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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.

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SC.912.N.1.7

How Measurement Errors Affect Results

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