Water in a pot boils and slowly reduces, until it dries up completely

Why

Kabir is trusting exactly what he can see — the pot looks completely empty, so 'gone' feels like the obvious word. But boiling doesn't destroy water, it just changes its FORM: the heat gives water particles enough energy to break free of the liquid and fly off into the air as invisible water vapour, one particle at a time. Nothing vanished — it simply spread out into the room as a gas too thin and scattered to see. Test: hold a cold steel plate above the boiling pot for a few seconds and watch — droplets of water appear on it almost at once, condensed straight out of the 'empty' air above the pot. Grandmother is right: the water became vapour and drifted into the room, it did not stop existing — the same water that leaves a boiling pot is part of why the air in a closed kitchen feels damp.