Definition:Scalar Quantity

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This page is about scalar quantity. For other uses, see Scalar.


A scalar quantity is a real-world concept that needs for its model a mathematical object which contains only one (usually numeric) component.



The mass of a body is a measure of how much matter it contains.

Mass is equivalent to inertia.

Mass also determines the degree to which a body creates or is affected by a gravitational field.

It is a scalar quantity.


Volume is the measure of the extent of a body.

It has three dimensions and is specified in units of length cubed.


Mass density is a physical quantity.

The mass density of a body is its mass per unit volume.


The speed of a body is a measure of the magnitude of its velocity, taking no account of its direction.

It is, therefore, a scalar quantity.


Temperature is a physical property of matter that quantifies how hot or cold a body is.

It is a scalar quantity which can be mapped directly to the real number line.

Electric Potential

An electric potential is the amount of work needed to move a unit of electric charge from a given reference point to a specific point in an electric field without producing an acceleration.

The reference point is usually either Earth or a point at infinity, although any point can be used.

Electric Charge

Electric charge is a physical quantity of matter which causes it to experience a force when near other electrically charged matter.

It is a scalar quantity.

It has been discovered by experiment that the corresponding force depends on the magnitudes of those electric charges, their displacements from each other, and their velocities.

Entropy (Physics)

Entropy is a property of a thermodynamic system.

It quantifies the number $\Omega$ of microstates that are consistent with the macroscopic quantities that characterize the system.

The entropy of a system is equal to the expectation of the value:

$k \ln P$


$k$ is a constant which relates the mean kinetic energy and absolute temperature of the system
$P$ is the coefficient of probability of the system.

Also see

  • Results about scalar quantities can be found here.