We explain what a magnitude is and the characteristics of scalar, vector and tensor magnitudes.
What is a magnitude?
By the term magnitude, in general, we must simply understand the measure of something. An object, a living being, a force of nature, all of this has measurable and quantifiable dimensions and features, which can be expressed through mathematical language, that is, magnitudes.
The word magnitude comes from Latin magnitudetranslatable as “greatness”, since in principle this term is applied to the dimensions of physical bodies, that is, concrete objects, each inscribed in a system of measurement or system of measurements.
Length, height, depth, for example, are dimensions expressible in units of measurement such as the meter, the kilometer or the centimeter. On the other hand, values such as a person's kindness or cruelty cannot be measured objectively, and therefore do not constitute magnitudes.
Thus, the magnitudes are a subject of study of physics. Each system of units and measurements available proposes its own standard based on which to carry out its measurements: the International System (SI), for example, proposes, as we said before, the meter as a unit of measurement of length. Now, magnitudes can be of three types, depending on their nature:
- Scalar magnitudes when they can be measured and expressed completely through a number, without it being necessary to explain any other meaning, such as direction. Its values can be independent of the observer, dependent on the position of the object, or on the movement of the observer. Examples of them are: length, temperature, mass, volume, time, electric charge, etc.
- Vector quantities for which a specific number is not enough to be measured, since they have an orientation or a sense that must be expressed through a vector: a line segment endowed with direction. This is the case of speed, force, acceleration, light intensity or electric field, for example.
- Tensor magnitudes those that respond to representations through changing models, depending on the state of movement or the orientation of the observer.
As we have seen, every magnitude is necessarily expressed as a set of mathematical units framed in a logical system. Some of them are conventional, arbitrary units, such as the meter, the kilogram or the second, while others are necessarily understood from combinations of conventional units, such as the Newton (kg. m /s2) or the Joule (kg. m2/s2).
However, the term magnitude It can also be used figuratively, to refer to the seriousness or importance of something as occurs in phrases such as “The magnitude of the events cannot be underestimated” or “the magnitude of my love is immeasurable”, meaning in those cases that it is something very big, that is, of proportions – figuratively – that are difficult to measure. measure big.
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References
- “Magnitude (mathematics)” on Wikipedia.
- “Physical magnitude” in Wikipedia.
- “Magnitude” in the Dictionary of the Language of the Royal Spanish Academy.
- “Magnitude” in ICT Resources of the Spanish Ministry of Education.
- “Physical quantities and units of measurement” at the Technological University of Pereira (Colombia).
