Remember how that nice BPA free bottle melted in a hot car? (but the skittles didn’t?) Obviously a cheapo water bottle would shrivel and disappear in a 1200°C campfire, right?
That’s about 2192 °F for our American readers.
Right. Yes. It will melt. And quickly!
Unless of course that bottle has some water in it. In fact, in a pinch you can boil water using a consumable plastic water bottle laid right in a fire.
The thin walls of the bottle quickly transfer the fire’s heat to the water inside. Water has a relatively high specific heat capacity, the amount of energy required to raise a substance 1°C, (4.18 J/(g*°C)) and a high boiling point at 100°C. Your plastic water bottle is likely made out of High-Density Polyethylene which has a melting point of around 115°C. The water maintains the bottle temperature below HDPE’s melting point, and so the plastic won’t melt.
With the cap off the steam from the boiling water can escape without any bursting. The bottle may soften and deform a little, but as long as there’s enough water for the heat transfer the plastic won’t melt.
Apparently this also works with a paper bag – which you can then cook an egg in.
You can usually find someone in the crowd willing to bet against this one. If you make any money on it, you’re welcome. And if anyone does the egg-in-the-paper-bag thing, send us a video!