Yes, water does evaporate in plastic bottles, but with an important nuance regarding the total amount of water present inside a sealed bottle.
Understanding Evaporation in a Sealed Bottle
Evaporation is a natural physical process where liquid water turns into a gaseous state, known as water vapour. This process is driven by energy, often in the form of heat.
According to sources, yes, it will get evaporated due to heat. Evaporation occurs because some water molecules gain enough energy to escape the liquid surface and become airborne vapour.
What Happens to the Vapour?
Inside a sealed plastic bottle, the water vapour created through evaporation doesn't have anywhere to go. The reference explains that evaporation converts water droplets into water vapours. Crucially, the water vapours will get collected on the walls of the bottle and will not escape into the atmosphere.
Because the vapour is trapped within the bottle, it can cool down and change back into liquid water, a process called condensation. This is why you often see small water droplets forming on the inside surface of a sealed water bottle, especially if the temperature changes.
The Effect on Total Water Content
Since the water vapour remains within the bottle and can condense back into liquid, the total amount of water substance (whether in liquid or gaseous form) within the sealed container remains constant. The reference confirms this, stating that because the vapour does not escape, certainly the water content in the bottle remains constant.
Think of it as water changing its state within a closed environment rather than disappearing entirely.
Key Points
Here's a summary of what happens:
- Evaporation Occurs: Water turns into vapour, driven by heat.
- Vapour is Trapped: In a sealed bottle, the plastic walls prevent the vapour from escaping.
- Condensation Happens: The trapped vapour often condenses back into liquid water on the inside surfaces.
- Total Amount Stays the Same: Although the balance between liquid water and water vapour might shift depending on temperature and pressure, the overall quantity of H₂O inside the sealed bottle does not decrease due to evaporation alone.
In essence, while the process of evaporation takes place inside a plastic bottle, the total volume of water doesn't decrease over time if the bottle is sealed, because the evaporated water remains trapped as vapour or condenses back into liquid.
