In our day to day life, one of the most interchangeably used words are mass and weight. Generally, people use these two words as the alternatives of each other, considering both similar. However, technically these two quantities are not the same. The crucial difference between mass and weight is that mass specifies the total amount of matter from which a body is composed. As against weight is specifically the earth’s gravitation pull on a body with a certain mass.
We know that every object experiences a certain pull towards the surface of the earth. This is due to the force of gravity applied by the earth on the object.
Gravity is the main factor of differentiation between the two.
Suppose a body is having a mass of 50 Kg then definitely its weight is not 50 Kg. However, in general usage, we say that the weight of the body is 50kg but that is technically incorrect. Mass and weight show direct proportionality with each other and the relation between the two is given as:
W = m.g
Here in this article, we will discuss how the two are differentiated in detail. But first, see the contents we are going to discuss here.
Content: Mass Vs Weight
Comparison Chart
| Basis for Comparison | Mass | Weight |
|---|---|---|
| Definition | The total amount of matter with which the object or body is composed of is known as mass. | The amount of gravitational force experienced by a body is known as weight. |
| SI unit | grams or kilograms | Newtons |
| Denoted as | m | W |
| Quantity type | Scalar | Vector |
| Value | It can never be 0. | Can be 0, when there is no gravity. |
| Location dependency | Do not exist | Exist |
| Quantity | Base type | Derived type |
| Variation in value | Remains same everywhere. | Varies with gravity. |
| Measured using | Ordinary balance | Spring balance |
Definition of Mass
We know that every object in this universe is composed of matter. This matter is made up of atoms while atoms are formed of protons, neutrons, and electrons. So, an object that occupies some space is composed of matter and the amount of matter present in the body defines its mass.
It is noteworthy here that the mass of the body is a physical property which remains constant irrespective of the rearrangement of particles inside the body. Thus, we can say that the mass of the body neither changes according to its location nor due to the gravitational force applied by the earth. This simply implies that it doesn’t matter whether the object is present on earth or the moon as in both the locations its mass will remain the same.
Generally, the mass of a body or object is measured in gm or kg and is considered as an intrinsic property of a material.
Definition of Weight
Weight is simply a force of attraction experienced by an object due to the presence of extremely heavy bodies like earth, moon, etc. Weight is an outcome of the universal law of gravitation.
We know the universal law of gravitation states that two bodies with certain masses attract each other where the force of attraction is proportional to the product of their masses and inversely proportional to the square of the distance of separation. However, as the earth is an extremely heavy body thus a body on its surface gets attracted towards it with a certain force.
So, weight specifies the force with which the object with a certain mass is getting attracted to the surface of the earth. Due to the reason that gravity is involved in the case of weight, therefore, the weight of bodies changes with location. This is the reason weight is different for the same body on earth and moon. Also, it shows the variation with higher and lower altitudes.
It is to be noted here that as a mass of the body shows direct proportionality with force thus, a body with more mass will experience greater force thus weighs more. While if the separation distance is very large then the force will be less hence the body weighs less.
Key Differences Between Mass and Weight
- Mass of a body shows the overall amount of matter from which it is composed. While the weight of a body is force existing between a body with certain mass and gravity.
- Mass is a scalar quantity as it has nothing to do with direction. However, weight is a vector quantity as here there is a force that acts down towards the earth.
- Mass of a body is independent of the location where the body is present. Whereas the weight of a body shows the variation with the location.
- A body is always composed of matter thus mass can never be zero. But as the weight of a body is a product of mass and gravity, thus it can be 0, in the absence of gravity.
- The SI unit of mass is gram or kilogram. However, the SI unit of weight is Newton.
- Mass is considered a fundamental quantity that is of independent nature while weight is known as a derived quantity.
- Mass of an object is measured using ordinary balance as it is determined by making a comparison between a known quantity and the unknown one. While spring balance generally measures the weight of objects.
- The mass of the body is independent of external factors. While the weight of the body varies according to change in external conditions.
Conclusion
So, this discussion clarifies that mass and weight are two interrelated but different quantities. This is said on the basis that mass is simply a quantity specifying the amount of matter present in it. But weight defines the force with which that mass is attracted to the earth.