Why is the density of a substance independent of sample size?

I suggest you look up and think about the definition of density.

Density is a measure of mass in a given volume. Doesn't matter what mass, if it's packed in a small enough volume, the total density will still increase exponentially.

Btw Capuchin, does density have an affect on the weight of the object as a whole?

I have a dense material i.e. Lead. I vaporize it into a large volume... Is it still as dense?:confused:

Jesus Christ... *rolleyes*

The whole point is that under normal conditions, a substance has a fixed density. So no matter how much of a material you have, the density (mass/volume) will stay the same.

If you increase the density then you increase the mass, so the weight increases too. But if you increase the density by compression of a certain amount of material into a smaller volume (like most examples of solidification), then density will increase but mass will not.