How to get the volume of an irregularly shape or solid?

Answer 1

Measure the volume of the water you have. Insert irregular solid. Measure the volume of the water you have now, and subtract the initial water volume from the new water volume. The difference in volumes is the volume of your irregular solid.

Answer 2

first you need to get the weight of the material and than you need to multiply it with its density. but you still need one parameter to multiply and square it with the previous multiplication.

Answer 3

Instead of water, you can use any liquid. But in order to gain a result with higher accuracy, you've to use a liquid which has a less viscosity.