Why do objects weigh more in vacuum than in air?

Objects do not actually weigh more in a vacuum compared to in air. Weight is the force exerted on an object due to gravity, and this force remains constant regardless of the medium the object is in. However, objects may appear to weigh more in a vacuum because there is no buoyant force acting on them, which is present in air and can partially counteract the force of gravity. This lack of buoyant force in a vacuum can make objects seem heavier when compared to their weight in air.