when did you observe that the air inside seemed to become foggy

1.        The air inside the bottle appeared to be foggy when the bottle was crushed and released. 2.       The Fog disappeared when the bottle was crushed again. 3.        The pressure inside the bottle is higher when the bottle is being crushed. 4.        The fog is observed when the pressure is low. 5.       The smoke particles are basically dust particulates which act as nuclei on which the water deposits to form a cloud. 6.       If the experiment is carried out without the smoke from the incense stick, then there is less chance of a fog forming as there won’t be any nuclei for the water vapour to deposit on