Abstract: A buoyant ball as provided within a water bottle to provide a momentary gate for restricting water flow out of the bottle as it is inverted. When filling the bottle with water, the ball floats on the surface and eventually comes to rest at the base of the bottleneck. Due to irregularities in the bottle, water flow past the ball is not prevented, but is restricted. As the bottle is inverted to permit water to escape therefrom, some water leaks past the ball through the neck and out of the bottle, but the ball remains positioned at the base of the bottleneck. The ball can be dislodged from the neck by an exterior blow to the bottle, or it will dislodge itself with the passage of time.