What would be different if this experiment was done with different size water bottles?

Say, I have a 2L water bottle that I do this experiment with. What would change is the amount of moles of water vapor I would have. Recall the conversion from liters to moles is 1 mole for every 22.4 liters. Thus I would have 0.089 moles of water vapor in our water bottle.

Next, let's assume that our final temperature is the same, but our initial temperature is 473 K (or 200 °C), therefore the change in temperature is 178.333 K.


Now, using our ideal gas-law, the pressure in the container is
0.089 * 0.0821 * 178.333
2
 = 0.653 ATM.
Say instead of a 2L water bottle, I have a 355ml water bottle. Thus I would have 0.016 moles of water vapor. Let's say that the initial temperature was 100 °C, but the surrounding temperature was colder, say 0 °C, or 273 K, Therefore the change in temperature was 100 K. Then, the pressure inside the container is
0.016 * 0.0821 * 100
0.355
 = 0.3884 ATM.

In conclusion, there are many variables that you can change in this experment that produce different results, you could see what happens when you only pour half of the water out, you could try using a milk carton. One thing you will notice is that while the changes in pressure are present, depending on the material of the water bottle you use, the results will or will not be noticeable. For water bottles of sturdier material, there may need to be an increase in the outside pressure to notice the compression, or you may need to have a bigger change in temperature. There are so many more variables that go into to this experment, but I'm sure you'll have fun tweaking the conditions in your experiments, so Keep calm and keep physics on.