What are you measuring when you put an objecct on a scale?

Answer 1

You're measuring one of the pair of gravitational forces between the Earth and the object.

The strength of the forces depends on the mass of the object and the mass of the Earth.

It also depends on the distance between their centers, but that's typically just the radius

of the Earth (the distance from the Earth's center to the surface).

The one we read on the scale is the force attracting the object to the Earth. It's what

we call the "weight" of the object on Earth.

The other force in the pair acts in exactly the opposite direction. That one is the force

attracting the Earth to the object. We don't have to measure it because it has exactly

the same strength as the first one. Nobody ever talks about it, but if we did, we would

have to call it the Earth's weight on the object.