The white gas emitted from the popsicle actually liquefies the water vapor in the air into small droplets, because the density of small droplets is greater than that of air, so the white gas should fall downward. The density of cold air is lower than that of hot air, so it will run down, driving these small water droplets to run down.

Extended data

The popsicle taken out of the refrigerator and the white gas ejected after the water is boiled are all formed by the liquefaction of water vapor. In winter, because water vapor comes out from the human body with heat, when you breathe, the water vapor coming out of your mouth suddenly meets external cold and liquefies into fine droplets, which change from gas to liquid and become fine droplets suspended in the air.

Water vapor is invisible. These so-called "white gas" are small water droplets. When the surrounding air meets ice cream, the temperature immediately drops and liquefies into small water droplets. The "white gas" of hot soup is formed because hot steam meets air and liquefies. So these two kinds of "white gas" are the same principle. The difference lies in the temperature.

Reference Baidu Encyclopedia-White Gas