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

Gli errori nel processo di misurazione sono un problema comune. Tali errori possono rientrare in due categorie: casuali e sistematici.
Gli errori casuali sono il risultato di un'incoerenza nel processo di misurazione o di variazioni nella quantità misurata. Questi si traducono in fluttuazioni, troppo alte o troppo basse, intorno al valore reale.
Considera uno scienziato che misura la lunghezza di un lombrico usando un calibro. L'incoerenza dello scienziato nel leggere correttamente le squame, o il movimento continuo del corpo del lombrico durante la misurazione, possono portare a misurazioni errate della lunghezza.
L'errore casuale non può essere evitato, tuttavia, può essere mediato con prove ripetute.
Gli errori sistematici sono il risultato di un problema persistente e portano a una discrepanza costante nella misurazione. Questi errori tendono ad essere troppo alti o troppo bassi rispetto al valore reale. Ad esempio, i pesi vengono misurati utilizzando una bilancia tarata in modo errato.
Questi sono prevedibili e per lo più legati allo strumento. Tuttavia, a differenza dell'errore casuale, non può essere mediato con misurazioni ripetute.

errori casuali e sistematici

Gli scienziati hanno sempre fatto del loro meglio per registrare le misurazioni con la massima accuratezza e precisione. Tuttavia, a volte si verificano degli errori. Questi errori possono essere casuali o sistematici. Gli errori causali sono osservati a causa dell'incoerenza o della fluttuazione nel processo di misurazione, o delle variazioni nella quantità stessa che viene misurata. Tali errori fluttuano dall'essere maggiori o minori del valore reale nelle misurazioni ripetute. Consideriamo uno scienziato che misura la lunghezza di un lombrico usando un righello. L'errore causale in questo processo di misurazione potrebbe essere il risultato del metodo incoerente con cui lo scienziato legge le scale, o se il verme si sta muovendo. L'errore casuale non può essere evitato; tuttavia, esso può essere tenuto nella media effettuando misurazioni ripetute.

L'errore sistematico deriva da un problema persistente e comporta una consistente discrepanza nelle misurazioni. Questi errori tendono ad essere sia consistentemente maggiori che minori del valore reale. Possono essere previsti e sono maggiormente di natura strumentale. Per esempio, una calibrazione impropria di una bilancia potrebbe portare ad attribuire agli oggetti un peso maggiore di quello avuto in realtà. Diversamente dall'errore causale, gli errori sistematici non possono essere tenuti nella media attraverso misurazioni ripetute.

Questo testo è adattato da <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>

Errori casuali e sistematici

Gli scienziati fanno sempre del loro meglio per registrare le misurazioni con la massima accuratezza e precisione. Tuttavia, a volte si verificano errori. Questi errori possono essere ...

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Physics Basics

Basi della Fisica

KEY TERMS AND CONCEPTS

TERMINI E CONCETTI CHIAVE

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

Measurement units, standards, and SI basics help scientists describe physical quantities clearly. A unit gives a number meaning, while a standard provides a fixed reference for that measurement. Together, they make results easier to compare and understand. The International System of Units, or SI, is the most common measurement system in science. It uses agreed-upon base units for common quantities. These standards reduce confusion when measurements are shared across labs, classrooms, and...

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

How Mass Differs from Weight

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acceleration due to gravity on earth

Free-Fall Acceleration on Earth

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tension

Tension in Ropes and Strings

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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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Measuring Error in Scientific Data

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