posted by Gabby ( 5 grade) .
this is a tough question and I don't get it. It says: What factor causes the difference between weight and mass?
Since this is not my area of expertise, I searched Google under the key words "weight vs. mass" to get these possible sources:
In the future, you can find the information you desire more quickly, if you use appropriate key words to do your own search. Also see http://hanlib.sou.edu/searchtools/.