Final answer:
A soft plastic bottle sealed at high altitude will dent inward when brought to a lower altitude due to decreased air pressure at higher altitudes, causing a pressure differential as you return to the valley.
Step-by-step explanation:
When you seal a soft plastic bottle or juice container while hiking high in the mountains and then return to the valley, the container will be dented inward due to decreased air pressure at higher altitudes. As you hike up a mountain, atmospheric pressure decreases, and if you seal a container at this high altitude, the air pressure inside the container is equal to the lower external air pressure.
However, as you descend back into the valley, the atmospheric pressure increases, but the pressure inside the sealed container remains at the lower level, causing a pressure differential. This results in the external higher pressure compressing the container inward.
In comparison, opening a bottle of sparkling water creates a different scenario involving atmospheric pressure. The carbon dioxide in the bottle forms bubbles because the drink is bottled under high CO₂ pressure, leading to a high concentration of dissolved CO₂. Once the bottle is open, this equilibrium is disrupted, causing the bubbles of CO₂ to rapidly exit the solution. If left open, the beverage will "go flat" as more CO₂ escapes.