Want to have some fun in winter? Throw a snowflake onto a soap bubble and watch it turn into an ice ball!
On a day with freezing temperatures and access to snow, blow a soap bubble. Let it burst. Repeat this “test” to be sure that the soap bubbles are bot freezing under this temperature. Now prepare a snowflake. Blow a soap bubble, and immediately throw the snowflake on the soap bubble. The snowflake will immediately slide down to the bottom of the soap bubble. The place where the snowflake would stop, would become the centre of crystallisation, and cause the whole bubble to be frozen.
Experiment by Dr Abram Teplitskiy. Wonders of Soap Films and Soap Bubbles.
P.S. By the way, did you know that a soap bubble consists of a thin layer of water trapped between two layers of soap?