What is the difference between mass and weight? Mass is the number of atoms an object is made up of. For example a living being is made up of Carbon, Oxygen, Nitrogen, Sulphur, Phosphorus, Hydrogen, and other atoms. So if you traveled to the moon, your mass will be the same as on Earth. Why? Because you are a whole person, nothing taken away or added. Weight is different, because weight has to do with the force of gravity which is different on Earth versus other celestial objects like the moon, Mars, etc. On Earth, gravity is 9.8 m/s2 or 9.8 meters per second squared. The moon is ⅙ the gravity on Earth or 9.8 m/s2 times ⅙. 1. So gravity on the moon would be 9.8 m/s2 divided by 6. What is the gravity on the moon? Don’t forget to include the units m/s2 .