Weight Vs. Mass
The strength of gravity depends in part of the masses on each of the objects. Mass is the amount of matter in an object. Because Earth is so massive, it exerts a much greater force on you than most materials. The measure of the force gravity on an object is called weight. Mass doesn't change, but an object's weight can change depending on its location. On the moon you would way about one sixth as much on Earth. This is because the moon has less mass than Earth, so the pull of the moon's gravity on you would also be less.