This is a fun funnel experiment that proves that an empty bottle isn't, in fact, empty and to fill it with water we need to make sure that air can escape. If a funnel is properly sealed to a bottle and a lot of water is poured into it at once, water should just stay in there and not go through to bottle. In our case, play-dough didn't make the seal completely air-proof (vortex in a funnel did not help too), but we had a chance to compare the speed of filling two bottles anyway #TheDadLab #presch