★英語聽力頻道為大家整理的英語聽力下載mp3：冰塊如何使飲品冷卻，供大家參考。更多閱讀請查看本站英語聽力頻道。
How Does Ice Cool Drinks?
Here’s something we tend to take for granted: drop a few ice cubes into a glass of water at room temperature, and in a few minutes the water will cool. How does this work?
Heat is a measure of molecular activity: the faster a thing’s molecules move, the more heat that substance contains. And because everything is made of molecules, and molecules are in constant motion, everything contains at least some heat.
As we know, ice is colder than room temperature water. Because ice molecules move slowly and cluster tightly together, they produce a relatively low amount of heat. When ice is placed in a glass of water whose molecules are moving at a greater rate, the ice begins to absorb energy, because heat always travels from regions of relative warmth to colder areas in order to equalize temperatures. In other words, ice absorbs heat from the water.
As the water molecules lose energy, they begin to slow down, and consequently to cool. So, it’s kind of the opposite of what we might think: when we put ice in water, the ice doesn’t give its cold to the water, it takes heat from the water.
The cooling process actually happens in stages. Because ice floats, it cools the water near the top of the glass first. As the top layer of water cools, its density increases, causing it to sink to the bottom. The lower layer, less dense and therefore more buoyant, floats to the top and is cooled in turn.
冰塊是如何使飲料冷卻的？
有件事情我們總覺得理所當(dāng)然：室溫下把一些冰塊放入水中，過幾分鐘水就會變涼。但這到底是什么原理呢？
熱量是衡量分子運動的一個指標(biāo)：一個物體分子的移動越快，物體所包含的熱量就越多。由于一切物體都由分子組成且分子總在不斷地運動，所以每個物體或多或少都包含著一些熱量。
我們都知道，冰的溫度要比溫水低。由于冰分子移動緩慢且相互連結(jié)得十分緊密，因此它們產(chǎn)生的熱量相對較少。如果把冰塊放入一杯分子移動較快的水中，冰塊就會開始吸收熱量，這是由于熱量總是會從高溫地帶轉(zhuǎn)移到低溫地帶，從而使溫度均衡。也就是說，冰塊從水中吸收熱量。
水分子在失去熱量后運動減慢，繼而水溫降低。這可能跟我們所想的恰恰相反：當(dāng)我們把冰放入水中，冰不會把自己的低溫傳給水，而是從水中吸收熱量。
這個冷卻過程實際上是分階段進行的。由于冰塊會浮在水面上，所以最上層的水會先變涼。上層的水冷卻后，它的密度會增大，上層的水會往下沉。而下層的水由于密度較小于是會上浮，進而又被冷卻，依次循環(huán)下去。
How Does Ice Cool Drinks?
Here’s something we tend to take for granted: drop a few ice cubes into a glass of water at room temperature, and in a few minutes the water will cool. How does this work?
Heat is a measure of molecular activity: the faster a thing’s molecules move, the more heat that substance contains. And because everything is made of molecules, and molecules are in constant motion, everything contains at least some heat.
As we know, ice is colder than room temperature water. Because ice molecules move slowly and cluster tightly together, they produce a relatively low amount of heat. When ice is placed in a glass of water whose molecules are moving at a greater rate, the ice begins to absorb energy, because heat always travels from regions of relative warmth to colder areas in order to equalize temperatures. In other words, ice absorbs heat from the water.
As the water molecules lose energy, they begin to slow down, and consequently to cool. So, it’s kind of the opposite of what we might think: when we put ice in water, the ice doesn’t give its cold to the water, it takes heat from the water.
The cooling process actually happens in stages. Because ice floats, it cools the water near the top of the glass first. As the top layer of water cools, its density increases, causing it to sink to the bottom. The lower layer, less dense and therefore more buoyant, floats to the top and is cooled in turn.
冰塊是如何使飲料冷卻的？
有件事情我們總覺得理所當(dāng)然：室溫下把一些冰塊放入水中，過幾分鐘水就會變涼。但這到底是什么原理呢？
熱量是衡量分子運動的一個指標(biāo)：一個物體分子的移動越快，物體所包含的熱量就越多。由于一切物體都由分子組成且分子總在不斷地運動，所以每個物體或多或少都包含著一些熱量。
我們都知道，冰的溫度要比溫水低。由于冰分子移動緩慢且相互連結(jié)得十分緊密，因此它們產(chǎn)生的熱量相對較少。如果把冰塊放入一杯分子移動較快的水中，冰塊就會開始吸收熱量，這是由于熱量總是會從高溫地帶轉(zhuǎn)移到低溫地帶，從而使溫度均衡。也就是說，冰塊從水中吸收熱量。
水分子在失去熱量后運動減慢，繼而水溫降低。這可能跟我們所想的恰恰相反：當(dāng)我們把冰放入水中，冰不會把自己的低溫傳給水，而是從水中吸收熱量。
這個冷卻過程實際上是分階段進行的。由于冰塊會浮在水面上，所以最上層的水會先變涼。上層的水冷卻后，它的密度會增大，上層的水會往下沉。而下層的水由于密度較小于是會上浮，進而又被冷卻，依次循環(huán)下去。