1 December 2023

In the world of physics and calculus, it is inevitable not to work with variables. Whether you are in the field of pure mathematics, chemistry, calculations related to electric current, the variables are there. But do you have a clear and precise idea of ​​what What does a physical variable mean?? Most likely, you have worked with this resource, but for sure, you do not have a well-defined concept of this.

It is for this reason that this article will help you with it. We will start with a complete definition of a physical variable, then we will move on to the characteristics that these have to end with the way in which a variable is measured or calculated.

Concept and definition of a physical variable

To respond to what is a physical variable, it is necessary to take into account a physical system X and the magnitudes involved. With this we can say that a variable of this nature allows define the magnitude within a physical system at one point. To understand this a little better, the most common magnitudes and variables in the field of physics are:

In this small list you will only find the independent variables most common in the field of physics. As you will notice, each of these are magnitudes that can be known thanks to the calculation of equations that each variable has. Now, in general terms, a physical variable can be defined or identified thanks to the following key points:

  • It has a physical magnitude.
  • It has a vector, so it has direction and meaning.
  • It is possible to calculate its value thanks to equations and formulas.
  • allows the study and understanding of a complex system.
  • Facilitates the collection and interpretation of data.
  • They can be applied to different scientific fields.

What are the characteristics of the variables?

Now that we’ve seen a clearer definition, it’s time to move on to the most important features about variables. Keep in mind that many of these can be applied even for the calculus of a chemical variable. Therefore, the following information will be useful for other scientific fields. Among the most notable features are:

  1. They have a general equation

It is important to differentiate an independent variable from a dependent one. On the one hand, we have the independent ones, which are not subject to changes during calculation or experimentation. While, on the other hand, there are those whose final value will depend on mathematical terms such as constants and independent variables already defined.

To all this, in physics there are mostly equations and formulas that allow us to find the value or magnitude of a variable. For example, if we want Calculate the distance between two points, we just have to have independent variables like speed and time. By using the general formula of distance, we can know what its physical magnitude is and along with it, give it a unit of measurement that corresponds to the need at that moment.

An additional feature at this point is that, thanks to the general physical equations, we can obtain variations of it. All this in order to adapt them to the calculation based on the independent variables that are available.

  1. Values ​​or magnitudes are not static

By this we mean that, depending on the values, constant and other elements that you have when calculating a variable, it can cause the final result to change. That is why, if we want to calculate the speed as a function of distance and a given time, it will never be the same if we modify the time parameter. This simple principle can be applied to any physical and mathematical field. Whether you’re working with energy, mining or space technology.

  1. They can be adapted to scalar or vector magnitudes

Variables have the particularity that they can be applied to calculate scalar and vector magnitudes. On the one hand, we can get real values ​​that we can express with numbers together with their unit of measurement. For example, when you calculate energy in an electrical system, the result you get is a scalar quantity. However, this is not always the case, since there is its counterpart, the vectors.

As for the vector magnitudes, these are differentiated or characterized by having a module, a direction and a sense. Both types of variables and calculations have a relationship with each other, however, a complicated algebraic procedure is required.

  1. They allow you to generate a hypothesis, test it or reject it.

For professionals who seek to propose an idea with solid foundations, it is necessary to have hypotheses that are supported by mathematical or physical calculations. It is there where the variables and their different variations come into play. It does not necessarily have to be a variable to be calculated or with scalar magnitudes, although the ideal would be to have clear and meaningful numbers.

It is thanks to the variables that a developed hypothesis can be verified, discarded or improved. In the event that the hypothesis yields favorable results, a theory is developed based on the values ​​obtained by calculating and using formulas.

What is the relationship between physical variables?

By this we mean that one variable can depend on another. For example, if you want to calculate the force of a body X, this is related to the mass and acceleration of that same body. That is, if you want to know what is the force possessed by a planet, you first have to know its mass and its acceleration in space. Thus, there is a relationship between the dependent variable Force and the independent variables mass and acceleration.

Thanks to the characteristics of the variables, we can use this simple equation to calculate the force from other bodies in motionno matter what its size. For this reason we say that the main characteristic of an unknown in physics is that its value is never static and adjusts to any calculation need.

So, generally speaking, there will always be a relationship between independent and dependent variables, regardless of constants. Without these elements present, it would become impossible to do any calculation, no matter how simple.

How are physical variables classified?

Now, there is a classification within the field of physics that is related to variables. We will detail each of these shortly.

What is a physical independent variable?

They are the best known and used in terms of calculus. it means. In fact, whether in physics, mathematics or chemistry, the independent variable fulfills exactly the same function. This is defined as an element that determines the final value of any value of a dependent variable. Taking the calculation of the distance traveled by a vehicle as an example, its final value will depend on both time and the speed of the vehicle, as long as the last parameter is constant.

In fact, within that simple calculation equation, there are two independent variables that acquire an X value depending on the case. This simple variation causes the final result to also be affected. For this reason, it is correct to say that there does not necessarily have to be a single independent variable. Since, for any calculation, there can be one, two or more variables, this will largely depend on the complexity of the equation.

What is a physical dependent variable?

Unlike the previous type of variable, these are characterized by depending on other elements, such as constants and independent variables. In fact, these are linked to physical mathematical formulas and equations. An example of this is the formula to know the force of a body. In its most general expression, its physical magnitude will depend on variables as the mass and acceleration of said body. Without these two elements, it makes its calculation impossible, which is why it is classified as a dependent variable.

How are physical variables measured?

In general terms, no variable can be measured because it is not something measurable, but rather calculable. Understanding this is easier than you think. You just have to keep in mind the following analogy:

  • Measurements are made with measuring instruments and tools.
  • Variables are calculated using values, constants, and independent variables.

Based on this described, the correct thing to do is to ask how the variables are calculated. Now, if you can measure a physical variable, as long as you have measuring equipment. For example, knowing the distance from one end to the other in a room. Here you use a meter to measure the variable “distance”. After you have this physical magnitude, you can use it to make the calculus of a more complex variable depending on the known parameter.

Keep in mind that, in order to make measurements and calculations, everything must be in its correct unit of measure. That is, if you want to calculate distance, you must use scalar quantities such as seconds and meters. This applies to the calculation of volume, time, power or energy, force, among others. So, in practical terms, it is possible to measure a variable as long as it is independent, otherwise, you will have to know other elements to proceed with the corresponding calculation.

What are the advantages and disadvantages of physical variables?

Regarding the advantages, we can mention some such as the following:

  • Allow quantify and qualify magnitudes.
  • They are of great help for scientific investigations.
  • Its application extends to any scientific field.
  • They adapt perfectly to any need.
  • Makes the data easy to understand.
  • They allow us to understand the functioning of a complex system.
  • A researcher can define what the independent variables will be.
  • It is possible to represent them graphically in mathematics.

Now, there are some disadvantages that, most likely, you should be very aware of. Among these are:

  1. A dependent variable can have many independent variables its value or magnitude may not be known.
  2. Physical math calculation is not always easy.
  3. It requires a series of processes to come up with a result.
  4. You need prior knowledge to be able to use them, as long as you work with numbers.
  5. In mathematical and physical problems, the variables are not well defined at first.

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