Name: measuring error in scientific data
Uploaded: 2023-09-22T11:49:39.000Z
Duration: 1 min 20 s
Channel: JoVE

Erros no processo de medição são um problema comum. Tais erros podem se enquadrar em duas categorias: Aleatórios e Sistemáticos.
Erros aleatórios são o resultado de inconsistência no processo de medição ou variações na quantidade que está sendo medida. Isso resulta em flutuações, muito altas ou muito baixas, em torno do valor real.
Considere um cientista medindo o comprimento de uma minhoca usando um paquímetro. A inconsistência do cientista em ler as escalas corretamente, ou o movimento contínuo do corpo da minhoca durante a medição, pode resultar em medições incorretas do comprimento.
O erro aleatório não pode ser evitado, no entanto, pode ser calculado com tentativas repetidas.
Erros sistemáticos são os resultados de um problema persistente e levam a uma discrepância consistente na medição. Esses erros tendem a ser muito altos ou muito baixos em comparação com o valor real. Por exemplo, pesos sendo medidos usando uma balança calibrada incorretamente.
Estes são previsíveis e principalmente relacionados a instrumentos. No entanto, ao contrário do erro aleatório, não pode ser calculado com medições repetidas.

erros aleatórios e sistemáticos

Os cientistas sempre se esforçam ao máximo para registrar medições com máxima precisão e exatidão. No entanto, às vezes erros ocorrem. Esses erros podem ser aleatórios ou sistemáticos. Erros aleatórios são observados devido à inconsistência ou flutuação no processo de medição, ou variações na própria quantidade que está sendo medida. Esses erros podem ser maiores ou menores que o valor real em medições repetidas. Considere um cientista medindo o comprimento de uma minhoca usando uma régua. O erro aleatório nesse processo de medição pode ser resultado do método inconsistente com o qual o cientista lê as escalas, ou se a minhoca está se movendo. O erro aleatório não pode ser evitado; no entanto, ele pode ser compensado com repetidas tentativas.

Os erros sistemáticos surgem de um problema persistente e resultam em uma discrepância consistente na medição. Esses erros tendem a ser consistentemente maiores ou menores que o valor real. Eles são previsíveis e, em sua maioria, de natureza instrumental. Por exemplo, uma balança de pesagem mal calibrada pode consistentemente pesar objetos como se fossem mais pesados que seus valores reais. Ao contrário do erro aleatório, erros sistemáticos não podem ser compensados com medidas repetidas.

Este texto foi adaptado de <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>

Erros Aleatórios e Sistemáticos

Os cientistas sempre fazem o possível para registrar as medições com a máxima exatidão e precisão. No entanto, às vezes ocorrem erros. Esses erros podem ser ...

Education

JoVE Core

Mechanical Engineering

Engenharia Mecânica

Unit 1

Unidade 1

Physics Basics

Fundamentos da Física

KEY TERMS AND CONCEPTS

TERMOS-CHAVE E CONCEITOS

Random and Systematic Errors

measuring error in scientific data

Random and systematic errors affect scientific measurements. Random errors cause values to spread around the true value. They make repeated measurements less consistent. Systematic errors shift measurements in the same direction each time.

Understanding both kinds of error helps students judge data quality. Random error can come from small changes during measurement. Systematic error can come from a biased tool or method. Scientists look for these patterns so they can improve results and interpret data more carefully.

Measuring Error in Scientific Data

introduction to scalers

Scalar Quantities in Physics

Scalar quantities in physics have size only. They do not include direction. This makes them different from vector quantities. Common scalar examples include mass, temperature, time, and energy. Each one can be described with a number and a unit. Because direction is not part of the value, scalars are often easier to compare and measure.

vector or cross product

Cross Product of Two Vectors

The cross product of two vectors gives a new vector that is related to both original vectors. It is also called the vector product. In many physics problems, this operation helps describe quantities that depend on direction as well as size. The result of a cross product has a direction set by the two input vectors. It is not the same as ordinary multiplication. The transcript focuses on the vector or cross product as a core vector operation students use when working with vectors in science.

introduction to vectors

Vectors in Motion and Direction

Vectors describe quantities that have both size and direction. They are used in physics to show how motion, force, and other quantities act in space. A vector can be represented with an arrow. The length of the arrow shows the size, and the arrowhead shows the direction. This makes vectors useful for comparing how one quantity points relative to another. Scalars are different because they have size only and no direction. Understanding the difference between vectors and scalars is an important...

units and standards of measurement

Measurement Units, Standards, and SI Basics

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accuracy and precision

Measurement Errors, Accuracy, and Precision

Measurement errors can affect how close a result is to the true value and how consistent repeated results are. Accuracy describes how close a measurement is to the accepted or true value. Precision describes how close repeated measurements are to one another. A result can be accurate, precise, both, or neither. A set of measurements may cluster tightly together and still be far from the true value. Another set may include values spread out from one another, even if one of them is close to the...

rules of significant figures

Counting Significant Figures in Measurements

Significant figures help students record measurements with the correct level of precision. They show which digits in a number are meaningful and which only help place the decimal point. In science class, this idea matters when writing and comparing measured values. The rules for significant figures explain how to count these digits in different numbers. Some digits are always counted, while others depend on where they appear in the number. Learning the rules makes it easier to report answers...

random and systematic errors

Random and systematic errors affect scientific measurements. Random errors cause values to spread around the true value. They make repeated measurements less consistent. Systematic errors shift measurements in the same direction each time. Understanding both kinds of error helps students judge data quality. Random error can come from small changes during measurement. Systematic error can come from a biased tool or method. Scientists look for these patterns so they can improve results and...

position and displacement

Tracking Motion with Position and Displacement

Position and displacement are key ideas in straight-line motion. Position tells where an object is located compared with a chosen starting point, called the origin. Displacement describes how far and in what direction the object has moved from its starting position. These ideas help describe motion clearly. Position can change as an object moves. Displacement focuses on the change in position, not just the path taken. That makes it useful for comparing motion in a simple and precise way.

position and displacement vectors

Using Vectors to Describe Motion

Position and displacement vectors describe motion in physics. A position vector shows where an object is located relative to a chosen origin. A displacement vector shows how far and in what direction the object moves from one point to another. These vectors are useful because they give a clear way to track movement in space. The video connects position and displacement to the idea of a reference point and shows how direction matters as much as distance. That makes them important for describing...

mass and weight

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tension

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gravitational force

How Gravity Acts Between Objects

Gravity is a force that pulls objects toward one another. On Earth, this force gives objects weight and keeps people, water, and other materials from drifting away. It also helps explain why planets and moons stay in motion around larger bodies. The strength of gravitational force depends on the masses of the objects involved. Larger masses create a stronger pull, while smaller masses create a weaker one. The distance between objects also matters, because gravity becomes weaker as objects move...

key terms and concepts

Learn how random and systematic errors affect scientific measurements, why they matter, and how they change the way students judge data quality.

Measuring Error in Scientific Data | JoVE K12

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mechanical engineering

Measuring Error in Scientific Data

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