Difference Between Mass and Weight

The key difference between mass and weight is that the mass does not depend on gravity, whereas the weight depends on gravity.

We often use the terms mass and weight interchangeably as synonyms, but they are different from each other. Mass is the measure of the amount of matter in a body while weight is the measure of the amount of force acting on a mass due to the acceleration due to gravity.

CONTENTS

1. Overview and Key Difference
2. What is Mass
3. What is Weight
4. Side by Side Comparison – Mass vs Weight in Tabular Form
5. Summary

What is Mass?

Mass is the measure of the amount of matter in a body. We can denote it using either m or M. Since it is a property of matter, it does not depend on gravity. This means, unlike the weight of a material, the mass is the same everywhere. Furthermore, mass cannot be zero because matter is everywhere.

Since mass has a magnitude, it is a scalar quantity. We can measure the mass using an ordinary balance. Usually, the unit of measurement is grams and kilograms.

What is Weight?

Weight is the measure of the amount of force acting on a mass due to the acceleration due to gravity. We denote it by W. The simple equation from which we can obtain the weight of an object is as follows:

Weight = m (mass)  x  g (acceleration due to gravity)

Since weight depends on gravity, it varies according to the location. Therefore, it increases or decreases with higher or lower gravity. Moreover, weight can be zero if there is no gravity, i.e. in space. Besides, weight is a vector quantity. It has a magnitude as well as a direction, i.e. directed towards the centre of the Earth.

We can measure weight using a spring balance; not all ordinary balances can measure weight. The unit of measurement is Newton (the unit of measurement of force).

What is the Difference Between Mass and Weight?

Mass is the measure of the amount of matter in a body. Weight is the measure of the amount of force acting on a mass due to the acceleration due to gravity. Hence, the key difference between mass and weight is that mass does not depend on gravity, whereas weight depends on gravity. Thus, the mass cannot be zero, but weight can be zero if there is no gravity, i.e. in space, there is no gravity.

Moreover, another difference between mass and weight is that the value of mass is a fixed value for a certain object, but the value of weight can vary depending on the location of the object.

Summary – Mass vs Weight

Though we use the terms mass and weight interchangeably, there is a distinct difference between mass and weight. The key difference between mass and weight is that the mass does not depend on gravity, whereas weight depends on gravity.

Reference:

1. Helmenstine, Anne Marie. “What Is the Difference Between Weight and Mass?” ThoughtCo, Mar. 21, 2019, Available here.

Image Courtesy:

1. “147629” (CC0) via Pixabay
2. “Spring scale – 3241” By Amada44 – Own work (CC BY-SA 3.0) via Commons Wikimedia