Vasoconstriction is an adaptation for survival because by restricting the blood flow to your “periphery” the more warm blood gets pumped to your vital organs keeping them alive, for example you might get frostbite on your fingers and toes because they are non essential, but your organs will be okay because the warm blood is keeping them from turning to ice. Humans adapted this way to survive in cold climates.
There is a place in the lid where the fluid rushes to when you tip it, leaving the air bubbles in the cylinder of the bottle. In some companies it's a chemical inside the fluid that can evaporate over time and looses it's " magic" effect.
