The weight of an object is the measure of of the gravitation force that acts on an object. When you weigh the objects on the scale, you are measuring the amount of force they feel due to the gravity of the earth at that point. Near the surface of the earth, the weight of an object is calculated by the formula, where is the mass, is the acceleration due to gravity. Since is constant at the location where the object's weights are measured, the only way their weights can be different is if they have different masses.