How is mass defined in physics?

Mass is defined in physics as a measure of the amount of matter in an object, and it is a constant that does not vary with location or gravitational conditions. This means that regardless of where an object is in the universe—whether on Earth, the Moon, or in space—its mass remains the same.

In contrast, weight is the force exerted on an object due to gravity and does vary depending on the local gravitational field. Therefore, it is essential to distinguish between mass and weight: mass remains constant, while weight changes with the strength of the gravitational pull acting on that mass.

Additionally, mass is not merely a reflection of the volume of an object. Although an object may possess a certain volume, its mass is determined by the density of the material it is composed of and the total volume, making them different concepts. Understanding that mass is a fundamental property of matter and consistent across varying gravitational contexts is crucial in physics.