[ELI5] how does ice melt faster/more stirred than just sitting?

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For instance, I make myself some hot coffee and I want to turn it to iced coffee. Stirring it seems to cool it down much faster than letting the ice just sit in the coffee, however, from what I have read, stirring the ice melts the ice faster and more even though it cools it down faster. Why? Is this even correct?

Also, would the ice just sitting in the hot coffee melt roughly the same amount as the stirred once the coffees reaches the desired cold temperatures? Idk we can make one up, coffee from 160°f to 40°f, I guess. I also generally fill my coffee cup completely with ice as I’m sure the amount of ice changes this.

I hope this makes sense and I tagged the question correctly. Thank you,

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13 Answers

Anonymous 0 Comments

When objects that are colder or warmer than their environment sit in one place, they change the temperature of the environment immediately around them. In the case of an ice cube sitting in a glass, the ice cube takes in some heat and the water around it becomes colder.

Because the water around it is colder, it does not warm up as fast. The heat from outside that cold area has to work its way through the cold water to reach the ice.

If you stir, you make the water move. When it moves, the cold water around the ice is replaced with warmer water. The ice is now touching warmer water and warms up faster.

The same thing is what causes “wind chill”. A human standing in still air will warm the air around their body, creating a pocket of warm air around them that keeps away the colder air. If there is a wind, that warmer air is blown away and replaced by colder air, causing you to cool off faster.

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