* Density is a measure of mass per unit volume. This means a denser material packs more mass into the same amount of space.
* Platinum is a much heavier element than silver. Platinum has an atomic weight of 195.08, while silver has an atomic weight of 107.87.
* Atomic weight directly relates to mass. This means a platinum atom is nearly twice as heavy as a silver atom.
Therefore, even if the rings are the same size (volume), the platinum ring will contain many more of these heavier atoms, giving it a greater overall mass and making it denser.
Here's a simple analogy: Imagine two boxes, both the same size. One box is filled with ping pong balls (light), while the other is filled with golf balls (heavier). The box filled with golf balls will be heavier because it has more mass packed into the same space. The same concept applies to platinum and silver.
