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News_of_Entwives t1_j6uina1 wrote

The energy released from the crystalization goes towards increasing the potential energy of the top of the water.

Freezing water releases energy to the surroundings, usually in the form of heat (the water gets colder, while the surroundings get warmer). It's the same effect as a handwarmer.... when the pack crystalizes, the energy released is absorbed by your hands, which get warmer.

In your hypothetical, (if the ball actually does raise up) I'd expect the water to freeze at an infinitesimally lower temperature than typical at your conditions.

I'd more expect the water to rise around the ball, but certainly can't know until doing it haha.

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mfb- t1_j6vl68j wrote

The ball will raise the water level in the container, which increases the average pressure, so the freezing point decreases by an extremely tiny amount.

We are talking about really small effects here. Freezing one liter of water releases 334,000 J. Raising a 10 gram ball by a centimeter needs 0.001 J.

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p1mrx t1_j6vs4an wrote

So that thermal energy "came from" the liquid water, and the water was liquid in the first place due to energy from the sun.

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earanhart t1_j6wesh6 wrote

Maybe not the Sun itself, any source of energy would work (some chemical reaction such as fire, nuclear, even mechanical energy from stirring the water would convert to some thermal energy), but yes. It was already in the water when the ball was floating.

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