Hey there! Hello!
The best answer I can give to you is that it depends. It depends on the way that the volume is being increased and if it's being increased along with the mass.
Volume represents the amount of space a substance, object, etc. takes up. Density represents the amount mass found in a given measurement of volume. Taking these definitions into account, we can see that volume directly correlates with the measurement of density.
Think of two buckets, one with one gallon of a substance and the other with two gallons of a substance. Both samples of the substance will have the same density, since mass was being added in addition to volume. Take a look at the example:
Bucket 1:
Mass of Substance = 1kg
Volume of Substance = 3cm^3
Density of Substance= 1/3 kg/cm^3
Bucket 2:
Mass of Substance = 3kg
Volume of Substance = 6cm^3
Density of Substance= 3/6 kg/cm^3 = 1/3 kg/cm^3
If we simply add substance, the mass and volume will increase together at a fixed rate, meaning that the most simplified version of the density fraction will always be the same.
But there's another part to this. You can increase or decrease the temperature of a sample, making volume increase/decrease and the mass stay the same. When you evaporate water, it turns to steam, which takes up much more space than it did as water. But nothing has been created or destroyed, so the mass stays the same. This would make the density change along with the volume.
I hope this helped you out! Feel free to ask me any additional questions if you need further clarification. :-)
