Fill a container completely full of water and place it in a catch-basin (another container). Submerge the cork in the container full of water, and measure the volume of the overflow.
You will note there are some errors involved in this method.
- it is difficult to tell how full "completely full" when water is involved
- it is difficult to submerge a cork without also submerging whatever it is that is holding the cork
- it is difficult to catch and measure all of the overflow, as some of it clings to the containers.
To avoid a couple of these problems, you can start with a container filled to a measured level, then see how the measure increases when you submerge the cork.
You will note there are some errors involved in this method.
- it is difficult to tell how full "completely full" when water is involved
- it is difficult to submerge a cork without also submerging whatever it is that is holding the cork
- it is difficult to catch and measure all of the overflow, as some of it clings to the containers.
To avoid a couple of these problems, you can start with a container filled to a measured level, then see how the measure increases when you submerge the cork.