Weight is a measure of the force exerted on an object due to gravity, defined mathematically as the product of the object's mass and the acceleration due to gravity ($W = m \times g$). While mass represents the amount of matter contained within an object and is constant regardless of location, weight is a force measurement that varies depending on the gravitational field strength; consequently, an object weighs less on the Moon than it does on Earth. In physical science, measuring weight requires instruments designed to measure tension or force, such as spring scales, and the resulting unit is typically expressed in Newtons within the International System of Units. Understanding the difference between mass and weight is fundamental to classical mechanics.