FAQ

What is the difference between Mass and Weight? Generally, people, treat them same term in practical life but in physics, they are very much different. One is in practical matter another is variable place to place, Hight to Hight depends gravity. What is gravity? force that exists among all material objects in universe. Express as g & it change place to place, Hight to Hight but one thing that is not change, this is it. It is Mass.

If you in Australia your mass is 59kg, if you in UK you are in 59kg if you in USA you are in almost 59kg, if you in Mars, obviously you are in 59kg. It can’t be change. This is just like your personality which never change other is your attitude which always chance place to place.

So, what is the definition of Mass?

Thousands of types of definition you will find in web but I like the following-

Mass can be defined as amount of matter present in you. No matter at what place you are may be in Africa or Europe its value remains constant.

What is the definition of Weight?

Weight is the force by which you are being attracted by this amazing planet. This is very much changeable from planet to planet & height to height. Gravity on Mars is 38 percent of Earth’s gravity, so a 100kg person on Earth would weight 38kg on Mars.

On the other hand, we can say that Mass is actually a physical quantity which measures amount of matter in a body whereas weight is actually the force with which earth pulls our body towards its own center.

How can we express them?

Generally, Mass is express by “m” and its S.I. unit is kg where as Weight is Expressed by “W” and its SI unit is N[Newton].

Weight is mainly the amount of forces force exerted by earth on a mass of any substance. Weight can be calculated as Weight=Mass x g, where g is acceleration due to gravity and its value is 9.8.

Let me explain,

If want to something buys from supermarket or any place where you prefer, may be online, they will mention mass of the Object not weight in practical though some of the company mention weight of the object but actually that it the mass of the object not weight of the object.

You will only get the weight of the object, when you multiply the value with “g”. So, if your weighing machine gives the reading for a object as 100kg then it weight will be 100×9.8=980N. Hope you got it.

Value of the weight is negligibly change in the earth surface as the value of the “g” is not significantly change on our planet surface but a little amount change in poles of the earth as the value of “g” slightly increase inversely in equator area the value decrease.

Evaluation of Mass & Weight

From the very beginning, people are involving their goods for trading. 2-pan balance scale and some reference weights were the primary transaction method to determine the quantity of item. Balance was achieved by placing unknown amount of goods to one pan and another pan contains reference weight. The main problem of the two pan scale was it can’t measure the force only measure the mass.

At the time of the advent of English, the traders referred their known item to compare to the another unknown item as “weights”, and this process known as weighing and thus the result ,mentions as weights at a little before 1000AD.

In late 1600, famous laws of motion developed by Isaac Newton’s but this is not quite accurate in extremely high speeds where theory of special relativity [Albert Einstein’s at 20th-century] is required. Mass depends on how much matter-atoms is an object.

Lot of research on relationship between the quantity of matter & effect of force on that matter, especially with the concept of gravity was performed by Newton & Hooke at 1600s. After the completion of the research, they publish their research paper in Latin as that time it was major communication medium in scientific research.

At 1700s, the Newton and Hooke works start to publish in English and in this process the decided the take the word “Weight” as amount of material which is already use for the centuries and its related to gravity and taking the word “Mass” [ which was unrelated meaning in that time] and having it mean to the amount of material [Similar meaning of Weight as that was using in that time]. So, the great confusion starts then. This was the fault of physicists & their translators.

Mass can be defined as the measurement of an object’s tendency to resist changing its own state of motion, well known as inertia. Left a football on a field will stay put or move in a straight line unless some force like friction, touch by foot or hand or creating obstacle to the line, it will keep moving forward. So much is the measure of force which will require to change its path.

Weight, can be defined as the measure of amount of downwards force that gravity exerts on a specific object. If the mass of the object increases then force increases, the more inertia it contains, then harder gravity pulls. On our Earth’s surface, force of gravity is almost 9.8 newtons per kg.

As the two term was confusing so people involve in trade, law, commerce had no interest to change the long use term “Weight” and continue it. Weight to them, physicists started calling mass already and this practice continue still today.

People who are involving in commerce & Law use the word “Weight” to define the amount of material where never involve the meaning of force and never implement the word “Mass”. At the year of 1750, spring scale was invented and it calibrated to read out the mass which surprisingly works very fine until it moved to significantly different strength of gravity. In our planet, the change of gravity is almost same until it Moves to poles or equator, if do so then change of gravity is not significant. So the traders continue to use the word “Weight” as they are using this term for a long period of time to define the word “Mass”.

At the period of time, physicists start proclaiming that the effectiveness of the Word “Weight” and “Mass” is correct and anyone who used them otherwise is very much incorrect and such shall be obsolete. This is totally insane as the physicists were violating the long-term usage of word “Weight”. They also emphasize the usage of word “Weight” referring forces. But this didn’t reflect the practical life. In practical life, in Commerce and Law, it is very much considered that the Weight is the synonyms of Massa and its correct is kilograms not newtons.

In this context, this is very much meaningful that “I weigh 99 kg” or “My weight is 99 kg” but as per Physics weight is the result of Mass and associated with gravity on its which unit is Newton not kilogram. As discussed, it can’t say forcefully that they are using the terminology incorrectly, moreover in some context the answer of the question is “There is no difference between “Weight and Mass” due to they are synonyms to each other and measured in kilogram.

But there is a clear distinction between the two terminologies where Mass is the amount of material which measured in kilogram and Weight is type of force with Mass measured in Newton. In technical field all of the measurements are associated with the Organization titled as “Weights and Measures”.

As per Scientists “Weight is measured in Newton[N] which is 9.8 times larger than Mass[m] in earth surface and this may vary from place to place [Earth to Moon, Earth to Mars, Earth to Saturn etc.] 10kg of Mass has Weight of 98N and this has the Weight in Moon has 10.6N in Moon.

To simply understand the difference between Weight & Mass is” Mass is the Personality of Matter and Weight is its own attitude which is variable to place to place”.

Mass is actually the intrinsic property of matter which is just like the like personality is of a man and weight is the gravitational pull on the specific object which depends on the other body which is employing on it which is similar to attitude depends on another party.

Expression of Weight and Mass
As per Physical Science, the Mass and Weight are the totally different and their expression is “m” for Mass and unit is kg where Weight express as m x g [g, acceleration due to gravity] and its unit is Newton.

Let consider Mass is m, then
Weight= m[Mass] x g[acceleration due to gravity]

What Is the Difference Between Weight and Mass?

In ordinary conversation, “mass” and “weight” are used interchangeably but they are very much different to each other. Mass is defined as the amount of material present in the matter where Weight is measured as how force of gravity acts on that mass. Amount of matter in a body is measured by mass and Express by “m” or “M”. The amount of force acting on a mass due to the acceleration due to gravity is measured by Weight and it’s the result of Mass multiplied by acceleration of gravity (g).

The values for mass and weight are the same if it does not move on Earth. If you change your location from low to or high to low gravity then the Weight of the Object shall be change but its mass remain same in any location as mass is not location dependent. You can think that your mass of the body is always same but your Weight shall be different on Mars compare to Earth.

Difference Between Mass and Weight

If I go other Planets then How Much I Weigh on there?

Due to acceleration to gravity the weight varies dramatically but person’s mass doesn’t change elsewhere in the solar system. The “surface” distance from the center of gravity plays a major role to calculate the gravity on the mass. When you travel on the top of the mountain [The Himalayas] your weight shall be slightly lower than the sea level. Always mass is not the major as mentioned before, distance plays a significant role.

Suppose, If I in Saturn, my weight will not increase Saturn 95.2 times as Saturn is 95.2 times heavier than earth due to its surface is so much far [1.4075 billion km from Earth] from the center of the earth. To get the actual weight of a person just multiply the appropriate number of Earth Gravity. For Example, 100-pound person shall be weight on 113.9-pound on Saturn or 1.139 times weight on Earth.

Different Surface Gravity on different Planet

Above the explanation, your weight will be same in Venus as the planet has the same size and mass as Earth. You feel slightly higher weight in Neptune and Saturn but less feel in gas giant Uranus. Almost same weight shall be assumed in Mercury and Mars though Mercury is much smaller than Mars[30% wider than Mercury].

If sun become cold [not possible in near future as assumed] you will feel 28 times much weight compare to Earth surface as it’s the more massive in our solar system.