That's weird! ! Bottled water without ice?

Without interference and impurities, the liquid does not form the core origin of ice crystals (usually dust and bubbles), and no one takes the lead, so it does not freeze.

However, once there is local interference and pollution, the supercooled liquid will start to form ice crystals at the interference place and start to grow and spread.

The icing doesn't all start, it has to start somewhere.

Refer to Baidu entry supercooling phenomenon

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Supercooling: The phenomenon that the actual crystallization temperature is lower than the theoretical crystallization temperature during crystallization. Under a certain pressure, when the temperature of the liquid is lower than the freezing point of the liquid under this pressure, the phenomenon that the liquid still does not solidify is called liquid supercooling, and the liquid at this time is called supercooled liquid. The purer the liquid, the more obvious the supercooling phenomenon. High purity water begins to freeze at MINUS 40 degrees Celsius. This is because the liquid is too pure and there is no "crystal nucleus" needed for solidification. When you have the necessary substances for solidification, such as throwing a little solid or shaking the liquid, you can make the liquid solidify quickly.