Mass is the measurement of how much space an object takes up, and weight is the measurement of the pull of gravity on an object. Scientists measure both mass and weight with the use of balances and scales. The formula weight equals mass times gravitational force equates the two measurements.
An object has the same amount of mass no matter its location. The weight of an object changes from location to location because of the effects of gravity. This means that from planet to planet, the force of gravity and therefore an object's weight changes, but mass remains constant.
An object's weight also changes with the fluctuations in gravity experienced across Earth's uneven surface. In general, gravity weakens the further away an object or location is from the surface of a planet. This means that Earth's gravity is weaker at the top of a mountain when compared to the gravity felt at the bottom of the sea. By knowing the gravity of a location or planet and an object's mass or weight on Earth, scientists utilize the weight to mass formula to predict any expected weight changes.
The larger the planet, the greater the gravitational pull and the more an item weighs. For example, an item that weighs 200 pounds on Earth actually weighs 468 pounds on the much larger planet Jupiter.