bearnybear Posted April 18, 2009 Share Posted April 18, 2009 An ice cube is placed in a glass of water at room temperature. Which heat exchange occurs between the ice cube and the water within the first minute? A. The ice cube gains heat, the water loses heat. B. The ice cube loses heat, the water gains heat. C. Both the ice cube and the water lose heat. D. Both the ice cube and the water gain heat. Wouldn't the ice cube start melting since room temperature is higher than its freezing point? That means it would need to gain energy to do so. That rules out choices B and C. But would the water in the cup get colder because of the ice cube or warmer because the ice cube is? Link to comment Share on other sites More sharing options...
Cap'n Refsmmat Posted April 18, 2009 Share Posted April 18, 2009 The water will give up some of its energy to the ice cube, since the ice cube is colder than the water. Heat always flows from hot to cold. Link to comment Share on other sites More sharing options...
bearnybear Posted April 18, 2009 Author Share Posted April 18, 2009 The water will give up some of its energy to the ice cube, since the ice cube is colder than the water. Heat always flows from hot to cold. Since the water loses energy, then the answer must be.. choice A! Thanks so much. I totally forget that heat goes from high concentration to low concentration!!! Link to comment Share on other sites More sharing options...
samtheflash82 Posted April 18, 2009 Share Posted April 18, 2009 Since the water loses energy, then the answer must be.. choice A! Thanks so much. I totally forget that heat goes from high concentration to low concentration!!! yes, always remember; "source to sink". the source of heat is the water, the sink for the heat is the ice cube. Link to comment Share on other sites More sharing options...
swansont Posted April 18, 2009 Share Posted April 18, 2009 Sorry if this isn't particularly helpful in this context, but … What an awful set of answers. Heat isn't a substance or property to be gained or lost. Heat refers to the transfer of energy, so if "heat" is used, all of those should be worded like "there is heat flow from A to B" In reality, one should replace the word with "net thermal energy" Saying that something heats up is fine — that describes an influx of energy which raises the temperature. But what you added to the system was energy. 1 Link to comment Share on other sites More sharing options...
guppyman Posted April 18, 2009 Share Posted April 18, 2009 I think the answer is A too. Link to comment Share on other sites More sharing options...
MM6 Posted April 18, 2009 Share Posted April 18, 2009 Actually none of the answers are correct. As swansont explained, heat is the flow of thermal energy (the vibratory motion of particles passed on to other particles). Choice A is the best answer, although it is not the correct answer. Just for your own knowledge replace the word heat for the word energy in all the answers. Link to comment Share on other sites More sharing options...
Kaeroll Posted April 18, 2009 Share Posted April 18, 2009 Since the water loses energy, then the answer must be.. choice A! Thanks so much. I totally forget that heat goes from high concentration to low concentration!!! Handy way to remember this: when you grab your pizza from the oven without oven gloves, which way does the heat flow...? Link to comment Share on other sites More sharing options...
bearnybear Posted April 19, 2009 Author Share Posted April 19, 2009 Handy way to remember this: when you grab your pizza from the oven without oven gloves, which way does the heat flow...? The heat goes from the source: the pizza, to the sink: my hands! Thanks! Link to comment Share on other sites More sharing options...
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