The density of a ping pong ball is not a fixed value, as it depends on the material it's made from.

Here's a breakdown:

* Celluloid ping pong balls: These are the classic type and have a density around 0.05 g/cm³ (grams per cubic centimeter).

* Plastic ping pong balls: These are often made from polypropylene or ABS plastic, with densities typically ranging from 0.9 to 1.1 g/cm³.

So, it's important to consider the material to determine the density of a specific ping pong ball.