Mass
Mass can be best understood as the amount of matter present in any object or body. Everything we see around us has mass. For example, a table, a chair, your bed, a football, a glass, and even air has mass. That being said, all objects are light or heavy because of their mass. In this lesson, we will learn what is mass, how to calculate it, and its examples while discovering interesting facts about it.
1.  What Is Mass? 
2.  What Is the Unit of Mass? 
3.  Difference Between Mass and Weight 
4.  FAQs on Mass 
What Is Mass?
In Physics, mass is the most basic property of matter and it is one of the fundamental quantities. Mass is defined as the amount of matter present in a body. The SI unit of mass is the kilogram (kg). The formula of mass can be written as:
Mass = Density × Volume
Note: The mass of a body is constant; it doesn’t change at any time. Only in certain extreme cases when a huge amount of energy is given or taken from a body, the mass may be impacted. For example, in a nuclear reaction, a tiny amount of matter is converted into a huge amount of energy, this reduces the mass of the substance.
What Is the Unit of Mass?
There are various units for calculating mass, like, kilograms, grams, lbs, pounds, etc., but the SI unit of mass is "kilograms" or kg. Every unit of mass can be converted to other units by using a proper conversion formula without affecting the meaning and essence of the quantity to be measured.
Note: 1kg is equal to 2.20462 pounds.
Difference Between Mass and Weight
People often get confused between mass and weight and they end up using these two terms interchangeably. However, mass and weight are two different terms and it is important to understand the difference between them. The difference between mass and weight is shown in the table given below.
Mass  Weight  

Definition  Mass is defined as the amount of matter in a substance  Weight is defined as the amount of force acting on the mass of an object because of acceleration due to gravity. 
Denotation  Mass is represented by “M.” 
Weight is represented by “W." 
Formula  •Mass is always constant for a body. •One way to calculate mass: Mass = volume × density. 
•Weight is the measure of the gravitational force acting on a mass. •Formula of weight: Weight = mass × acceleration due to gravity 
Unit of Measurement  The SI unit of mass is "kilogram".  The SI unit of weight is Newton (N). 
Quantity Type  •Mass is a base quantity. •Mass only has magnitude and hence, it is a scalar quantity 
•Weight is a derived quantity. •Weight has both magnitude and direction (toward the center of gravity) and hence, it is a vector quantity. 
Measuring Instrument  Mass can be easily measured using any ordinary balance. For example, beam balance, lever balance, pan balance, etc. 
Weight can be measured by a spring balance or by using its formula given above. 
Did you know that we have different weights on the earth, the moon, and in space? However, our mass is the same everywhere.
Now, let us look at some important facts related to mass:
 Mass only has magnitude, hence, it is a scalar quantity.
 Weight has both magnitude and direction; it is a vector quantity.
 Mass can also be defined as "stored energy in particles."
 Mass represents the total atoms or particles that it contains.
Solved Examples on Mass

Example 1: Sam weighs 1000 lbs on Earth. On some other planet, the weight of Sam would be 38% of that on Earth. How much would Sam weigh on that planet?
Solution: We know that Sam's weight on earth is 1000 lbs and his weight on another planet would be 38% of that on Earth. Therefore, Sam's weight on another planet= 38% × his weight on the Earth = 0.38 × 1000 lbs = 380 lbs 
Example 2: The mass of an object is 6,000 pounds. Calculate its mass in tons.
Solution: We know that 1 ton = 2000 pounds. Thus, 6000 pounds = 6000/2000=3 tons. 
Example 3: Damian has a book that has a mass of 2.2 kg. What is the weight of the book on the Earth?
Solution:
Mass of text book = 2.2 kg and acceleration due to gravity = 9.8 m/s^{2}.
Weight formula = \(\text {mass} \times \text{acceleration due to gravity}\)
Weight of text book \(= 2.2 kg \times 9.8 m/s^2 \)
Weight of textbook = 21.56 N
Therefore, the weight of the textbook on Earth is 21.56 N.
FAQs on Mass
Does Air Have Mass?
Yes, air has mass. For example, an inflated balloon weighs heavier than a deflated balloon, which proves that the air inside the inflated balloon has mass.
Are Mass and Volume the Same?
Mass is the amount of matter that an object is made up of. Volume is the amount of vacant space that an object takes up. Hence, mass and volume are not the same.
Are Density and Mass the Same?
Mass measures the amount of matter present in a substance. Density shows the amount of matter in a given space for a substance. Density and mass can be the same as unit volume.
Are Weight and Mass the Same?
No, weight and mass are not the same. Weight is the amount of force acting on a body and mass is the amount of matter in a body. Weight can be changed depending upon the force while mass is constant.
What is the S.I Unit of Mass?
The S.I Unit of Mass is Kilograms (kg).
What is Mass Formula?
The formula used to calculate the mass of an object is, Density × Volume.