Though used interchangeably, there are prominent differences between mass and weight in the field of natural sciences–particularly in physics.

Introduction

Have you ever wondered, why we feel differently when we are standing on a stationary lift vs a moving lift? These experiences are related to two important scientific concepts: mass and weight. We often use these terms interchangeably, but they are quite different.

What is Mass?

Mass is the amount of matter in an object. It is a measure of how much “stuff” an object contains, and it does not change regardless of location.

Key Properties of Mass

Some key properties of mass are as follows:

1. Representation

Mass is represented by the symbol ‘m’.

2. Unit

In the SI system of units, mass is typically measured in kilograms (kg).

3. Type of Quantity

Mass is a base quantity in the SI System of units. It is also called as the fundamental base quantity.

4. Nature of Quantity

Mass is a scalar quantity as it only needs magnitude for its complete description.

5. Effect of Gravity

Mass is independent of gravity, meaning, it does not change whether we are on Earth, the Moon, or in space.

6. Constant Parameter

Mass remains the same for an object unless more matter is either added or removed.

7. Instrument Used

A balance scale (e.g., electronic balance, lever balance, etc.) is used to measure the mass.

What is Weight?

Weight is the force exerted by gravity on an object. It depends on both the mass of the object and the gravitational pull of the planet or location.

Key Properties of Weight

Some key properties of mass are as follows:

1. Representation

Weight is represented by the symbol ‘W’.

2. Unit

In SI system of units, weight is measured in newton (N).

3. Type of Quantity

Weight is a derived quantity in the SI System of units. It is a combination of two other physical quantities, namely, mass and gravitational acceleration.

4. Nature of Quantity

Mass is a vector quantity because it requires both magnitude and direction for its complete description.

5. Effect of Gravity

Weight is dependent upon gravity, meaning, it is not free from the influence of the gravitational pull of the Earth, the Moon, etc.

6. Variable Parameter

Weight does not remain the same for an object, for instance, the weight on the Earth (stronger pull) is different from the weight on the Moon (weaker pull).

7. Instrument Used

A spring scale is used to measure the weight.

Comparison of Mass and Weight

Here are simple differences between mass and weight:

Why the Differences between Mass and Weight is Important?

The distinction is essential for practical and scientific reasons. Understanding the differences between mass and weight is crucial because they affect how we measure and interact with the world. For example:

• Science Experiments: Measuring mass ensures accuracy, regardless of where you are on Earth or in space.
• Space Exploration: Astronauts’ weight changes in space due to gravity, but their mass remains constant.
• Everyday Life: Knowing the difference helps in fields like cooking, sports, and engineering.
• Accuracy in Measurements: Mass gives consistent results, making it more reliable in calculations.
• Understanding Gravity: Weight helps explain gravitational forces and their effects.
• Applications in Space: In space missions, scientists use mass since weight becomes negligible.
• Daily Use: From grocery shopping to engineering, knowing the difference prevents confusion.

By understanding these concepts, we can grasp a better understanding of how the physical world operates.

Key Properties of Matter

Both mass and weight are properties of matter. Here is a quick overview of general properties matter:

• Volume: The space an object occupies.
• Density: How tightly packed matter is.
• Inertia: The resistance of an object to changes in its motion.

Mass and Weight of the 3 States of Matter

The simplest distinction between the 3 states of matter is as follows:

Solids

• Mass: Fixed and measurable.
• Weight: Depends on gravity.

Liquids

• Mass: Measured using a container.
• Weight: Changes with location but measurable with a spring scale.

Gases

• Mass: Determined by capturing the gas in a container.
• Weight: Depends on both gravity and air pressure.

Conclusion

Mass and weight although used interchangeably, are different concepts in the field of physics. Mass measures how much matter an object contains, whereas, weight measures the force of gravity acting on it. Recognising their differences is essential for understanding the fundamentals of science.

Frequently Asked Questions (FAQs)

What is mass in simple terms?

Mass is the amount of matter in an object, and it doesn’t change with location.

What is weight in simple terms?

Weight is the force of gravity acting on an object.

Why does weight change on the Moon?

The Moon has less gravity than Earth, so the weight of an object is less there.

Does mass ever change?

No! It only changes if we add or remove matter from the object.

What unit is mass measured in?

Mass is measured in kilograms (kg) or grams (g).

What unit is weight measured in?

Weight is measured in newtons (N).

Why is mass constant but weight not?

Mass is independent of gravity, while weight depends on gravitational force.

How is mass measured?

Using a balance scale.

How is weight measured?

Using a spring scale.

Can you weigh something in space?

No! It is because there is no gravity, but we can still measure its mass.