SHM problem

[Physicsisfun2005]

A hollow spere, radius 0.20m is attached to the end of a 0.80m long string, hung vertically and used as a simple pendulum.


The sphere is filled with water. Suppose there is a small hole in the bottom of the sphere. As the filled sphere swings back and forth, water slowly drains.

Question: If this has no effect on the period explain why. If it does affect the period describe how the period changes and why.

[Doc Al]

How does the period of a simple pendulum depend on its mass?

[Physicsisfun2005]

thats what i thought. I know that mass doesn't effect the period...i thought that the drainage might affect the motion.