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

Los errores en el proceso de medición son un problema común. Estos errores pueden clasificarse en dos categorías: aleatorios y sistemáticos.
Los errores aleatorios son el resultado de inconsistencias en el proceso de medición o variaciones en la cantidad que se mide. Esto da lugar a fluctuaciones, demasiado altas o demasiado bajas, en torno al valor real.
Considere a un científico que mide la longitud de una lombriz de tierra usando un calibrador. La inconsistencia del científico para leer las escalas correctamente, o el movimiento continuo del cuerpo de la lombriz de tierra durante la medición, puede resultar en mediciones de longitud incorrectas.
El error aleatorio no se puede evitar, sin embargo, se puede promediar con intentos repetidos.
Los errores sistemáticos son el resultado de un problema persistente y conducen a una discrepancia constante en la medición. Estos errores tienden a ser demasiado altos o demasiado bajos en comparación con el valor real. Por ejemplo, pesos que se miden utilizando una balanza de pesaje mal calibrada.
Estos son predecibles y en su mayoría están relacionados con instrumentos. Sin embargo, a diferencia del error aleatorio, no se puede promediar con mediciones repetidas.

errores aleatorios y sistemáticos

Los científicos siempre intentan registrar las mediciones con la máxima precisión y exactitud. Sin embargo, a veces ocurren errores. Estos errores pueden ser aleatorios o sistemáticos. Los errores aleatorios se observan debido a la inconsistencia o fluctuación en el proceso de medición, o a las variaciones en la magnitud misma que está siendo medida. Tales errores fluctúan entre ser mayores o menores que el valor real en mediciones repetidas. Considere a un científico midiendo la longitud de una lombriz de tierra usando una regla. El error aleatorio en este proceso de medición puede ser el resultado del método inconsistente en el que el científico lee las escalas, o si la lombriz de tierra se está moviendo. El error aleatorio no se puede evitar; sin embargo, se puede promediar con ensayos repetidos. Los errores sistemáticos surgen de un problema persistente y resultan en una discrepancia constante en la medición. Estos errores tienden a ser consistentemente mayores o menores que el valor real. Son predecibles y en su mayoría son de naturaleza instrumental. Por ejemplo, una balanza de pesaje incorrectamente calibrada puede pesar consistentemente objetos más pesados que su valor real. A diferencia del error aleatorio, los errores sistemáticos no se pueden promediar con mediciones repetidas. Este texto está adaptado de <a href="https://openstax.org/books/chemistry-2e/pages/1-5-measurement-uncertainty-accuracy-and-precision">Openstax, Chemistry 2e, Sección 1.5: Incertidumbre de medición, exactitud y precisión.</a>

Errores aleatorios y sistemáticos

Los científicos siempre hacen todo lo posible para registrar las mediciones con la máxima exactitud y precisión. Sin embargo, a veces se producen errores. Estos errores pueden ser ...

Education

Educación

JoVE Core

Physics

Física

Unit 1

Unidad 1

Units, Dimensions, and Measurements

Unidades, dimensiones y mediciones

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

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

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...

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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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solving problems in physics

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Physics problem solving uses general physical principles to work out specific situations. It is a key skill in physics, and it can also help with everyday life. The same analytical skills can be used in new situations, while a list of facts can never cover every possible case. Solving physics problems also takes creativity and insight. These skills grow with experience and practice. There is no simple step-by-step method that works for every problem, but a three-stage process can guide the...

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 Física presenta la teoría y la aplicación de conceptos físicos fundamentales, como la cinemática, dinámica, mecánica de fluidos, estática, ondas y acústica, mediante animaciones audiovisuales concisas y fáciles de entender. Además, los vídeos de científicos en acción muestran la aplicación de los conceptos relacionados en experimentos de investigación clásicos y originales, realizados en laboratorios de todo el mundo.

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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.1.6

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SC.912.N.1.7

How Measurement Errors Affect Results

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