Complex sentence: The intent is to loosen or break up a, excessive material, plunger is much more effective when there is water in the pipe because water does not compress and will thus transmit more of the applied force than air.
Split into simpler sentences: The intent is to loosen or break up a, excessive material. A plunger is much more effective when there is water in the pipe because water does not compress and will thus transmit more of the applied force than air.