Mass vs. Weight: Understanding the Difference.

Mass and weight are related but separate concepts in physics. Mass is an intrinsic property of an object, while weight is the force exerted on an object's matter by a gravitational field. The equivalence principle states that gravitational mass and inertial mass are equivalent. Buoyancy explains why floating objects still have weight, as they displace fluid and experience an upthrust equal to the weight of the fluid displaced. The weight of an object is spread out across the planet's atmosphere when it flies, making it difficult to measure.