The animated demo demonstrates the continuity principle in one-dimensional steady flow: as water accelerates downward under gravity, its velocity increases, and to maintain a constant mass flow rate, the linear density and cross-sectional area of the stream must decrease. This explains why a stream of water from a faucet becomes visibly narrower as it falls—a clear, observable consequence of mass conservation and the inverse relationship between velocity and area in steady fluid motion.
water exits a faucet and accelerates under gravity while its velocity increases as it falls-L.mp4