OK, I've googled it, I've tried to make sense of it, but I still have this one thing in my head that doesn't go away. Mass vs volume. What is the difference between the two. If mass is the amount of matter,matter contains and volume is the space enclosed by matter; then it's basically saying how much space there is in an object or shape? Also I keep stumbling upon that there are different types of mass like inertial mass or gravitational mass, are they classified by a formula of such? Reason why I'm asking is because I'm starting to learn physics in a book to get ready for college since I've lost a lot of memory since high school.