In a busy kitchen, you reach for a sponge to clean the counter. Under the faucet, it draws in water, swelling evenly while containing every drop. It wipes surfaces clean, moving without trails of moisture left behind.
You scrub the sink next, then the stove. The sponge takes on more liquid from the wet spots, growing sodden and heavy. Still, it retains all the water—no escapes, no spots on the floor.
The limit arrives precisely when the sponge can hold no more. Internal pressure forces a drop to form at the underside and detach, landing on the floor below.
Up to that instant, the sponge keeps water fully enclosed. The next moment brings successive drops, creating visible wet marks that spread outward.
Cleaning shifts across the line. The sponge moves from captor of water to releaser of it.