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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Imagine you had a bowl of cinnamon-raisin oatmeal that was really hot, and you wanted to cool it off by blowing on it. You start off blowing pretty hard but as you keep blowing you start to run out of breath so you blow weaker.
So, to really cool down your oatmeal, you invite every kid you know over to blow on your oatmeal, but there’s only so much space around your bowl of oatmeal, so while it’s going faster with more kids, it’s still not cooling down as fast as you want.
Then you realize that if you get your friends to start blowing on the oatmeal as hard as they can, and then move out of the way before they start running out of breath, you can pretty much have a constant long stream of air blowing on your oatmeal, and this cools it off much faster.
Ice is much like your friends in the story. It cools things off faster at the beginning but slows down as the temperature around the coffee equalizes, but if you constantly replace the ice, you’ll maximize the heat transfer.
Thank you so much everyone, and all of y’all are so nice too! 🙂 this was great, and also some of the examples happened to be funny too me, which I liked. I am more knowledgeable now lol
You are absolutely right, stirring does speed it up 🙂
Let’s look at why:
First, I’m sure you’ve heard this before but “energy cannot be created or destroyed”, so in order for the ice to heat up and melt it needs the coffee to cool down. So by making the ice melt faster you are necessarily cooling the coffee faster. The heating of the ice is connected directly to the coffee cooling.
It’s like a convection oven. When stirred, the heat transfers faster, which melts the ice faster, which in turn cools the coffee because of the connection.
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