Explainer: What’s the difference between mass and weight?
Though mass and weight are related, they’re actually quite different things. Jake Port explains.
We often use the words ‘mass’ and ‘weight’ interchangeably, but they mean quite different things. Your mass is the same no matter where you go in the universe; your weight, on the other hand, changes from place to place. Mass is measured in kilograms; even though we usually talk about weight in kilograms, strictly speaking it should be measured in newtons, the units of force.
Mass is a measurement of an object’s tendency to resist changing its state of motion, known as inertia. Left to its own devices, an object will stay put or move in a straight line - think of a puck on an air hockey table. Unless some force - like friction, or banging into a wall - acts on the puck, it will keep sliding on the same path forever. Mass is a measure of how much force it will take to change that path.
https://cosmosmagazine.com/physics/explainer-what-s-the-difference-between-mass-and-weight