The mass of an object does not change whether it's on the Moon or on Earth. Mass is the amount of matter in an object, and it's an intrinsic property that doesn't depend on location.

However, the weight of an object does change on the Moon. Weight is the force of gravity acting on an object's mass. Since the Moon has a weaker gravitational pull than Earth, an object on the Moon will weigh less than it does on Earth.

Here's a simple way to think about it:

* Mass: How much "stuff" is in something.

* Weight: How hard gravity pulls on that "stuff".

So, while the object's mass stays the same, its weight will be different on the Moon because of the weaker gravity.