Scalar

In physics, scalar (scalar Quantities) are generally physical quantities that are unchanged by changes to a vector space basis. Scalar are often associated with units of measurement.  The change of the vector space basis changes the vector definition according to the basis changes the description of a vector in terms of the basis used but does not change the vector itself, while the scalar does not have any effect with these changes. 

This physical definition of scalar, in previous theories, such as Newtonian mechanics, implies that rotation or reflection preserve scalers, while in relativistic theories, the transformation of Lorentz or the translation of space time preserve scalars.

Generally Scalar is a physical Quantity which is defined only by its magnitude. This means that there is only one piece of information needed to define the scalar quantity. Consider the height of a structure. Eighty feet represent the height of the structure. If you also have the width and depth of it, you can find another scalar value of the structure, its volume. 

When a measure of magnitude corresponds to a directional element, it becomes a vector, defined as the magnitude and direction of an object, such as velocity or displacement. The directional component  can be defined by directions (north, south, east, west, etc.) or by directional words or symbols such as right or left, up or down, or positive or negative direction, or forward and backward. In physics, positive (+) or negative (-) symbols can indicate direction.

Magnitude

A Magnitude is a numerical quantity that represents the size, value, or distance of an object such as speed or mass or density, or length. It is usually a representation of the size of objects. Scalars and vectors both have the same magnitude.

Magnitude is given by number and unit. A random number is not a scalar or vector; 25 itself means nothing, but if you add a unit, you have a scalar value. If you add a unit and a direction then now you have a vector value.

Examples of Scalar Quantities

In physics, basically scalar Quantity is used for several pieces of information. Distance, speed, force, weight, force, time, and temperature are all scalar measurements. These are used for their informational aspects and their role in calculating some of the values ​​required in physics. This can be seen by using distance and time to calculate speed.

Other examples of scalar values ​​are distance, density, energy and time. Generally a distance, for example, can be represented by a number and a unit of measurement, such as 150 km or 10 miles. Energy can be measured in joules (J) like 8.70 J for power. 

The density is the mass per unit volume and thus there is a unit of grams per cubic centimetre. However, density is expressed only as a numerical value (for example, the soil density is 5.51 g / cm ^ 3). It is not a vector because it has no directional component.

Mass and speed are also two examples of scalar values.

Speed:

Generally speed ​​is the scalar quantity in nature. It is the change in the distance travelled by an object, while velocity is the vector quantity and defined as the speed of an object moving in a certain direction.

Conclusion

In this article we have studied about scalar quantity. Scalar, a physical value that is fully defined by its magnitude; examples of scalar are volume, density, speed, energy, mass, and time. Some values, such as force and velocity, have both magnitude and direction and are called vectors.

Scalars are defined by real numbers that are usually but not necessarily positive. Scalars can be manipulated by the basic laws of algebra.