When mass increases does density increase or decrease?
For example: Think of a room filled with balloons that are filled with air. Imagine that the room can hold 50 balloons that are filled with air. If you fill that room again, only this time, with empty balloons, you could fill that room with many more balloons, perhaps thousands, in the room that could previously only hold 50 when the balloons were filled. Because you can fill the same sized room with much more balloons, you are increasing the balloon density in the room. Now imagine that each of those original 50 filled balloons have a mass of 1 gram, so there are 50 grams of balloons in the room. An increase of thousands of empty balloons would dramatically increase the amount of mass in the room, to thousands of grams. Therefore, an increase in density in a static volume will also increase its mass.
