Are the ice flowers on the windows inside or outside the glass in winter? How are ice flowers formed?

In winter, ice flowers will be tied to the inside of the window glass.

This situation of forming window grilles is called sublimation. The principle is that in winter, the temperature of water vapor in the room is higher than that of glass. When it meets very cold glass, it will directly change from gas to solid, forming small ice crystals, thus forming ice flowers.

This process is exothermic, and the outdoor water vapor temperature is similar to that of glass, so there can be no condensation on the glass outside the house. Generally speaking, the heating effect of buildings in cities is very good, so this phenomenon rarely appears, and it is often seen in rural houses.

Extended data:

Snowflakes are formed by magnifying small ice crystals, and the molecules of ice are mostly hexagonal, so snowflakes are mostly hexagonal. The diversity of snowflake shapes is closely related to the water vapor conditions when it is formed.

Hexagonal flake ice crystals have different saturated vapor pressures because of the different bending degrees of their surfaces, edges and corners, of which the saturated vapor pressure on the edges is the largest, followed by the edges and the plane is the smallest.

When the actual vapor pressure is the same, the growth of sublimation is different because of the different saturated vapor pressures on the surface, edge and corner of ice crystals. If the water vapor in the cloud is not very rich, the actual water vapor pressure is only greater than the saturated water vapor pressure on the plane, and the water vapor only condenses on the surface, then a columnar snowflake is formed.

References:

Baidu encyclopedia-ice flower