Eric Tolman Computer Scientist Weight is the term scientists use to describe how much force due to gravity acts on an object. The amount something weighs depends on two things, how much mass the object has, and how strong the force of gravity is where the object is at. Mass is a term that describes how much of an object there is. Every atom has a certain mass, and the more atoms there are, the more mass an object has. Every physical object has mass, and this mass is the same no matter where it is.
Gravity is a force that pulls on things.
Just like if you push something across the table, your push is a force. There are many different types of forces, but forces are not physical objects, they are more like actions. Since forces are not objects, they do not have mass. How much something weighs is determined by multiplying the mass of the object by the force of gravity acting on the object. Forces have no mass, so they never weigh anything.