高深的水問題謝謝入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入入

有些液體加壓時它會變成固體，但有些固體加壓卻可以變液體。一般物質是前者，但小數物質如水卻是後者。為什麼有這樣的結果，這便是你所說的體積變化問題。
一些物質(大多數都少這種物質)凝固時體積會減少，這種物質加壓時較易由液體變成固體。但如水的凝固時體積會增加，加壓時便容易由固體變成液體。
例如在科學上有一個叫復冰實驗。如下圖所示：

圖片參考：http://hk.geocities.com/namsm4e/P27.jpg

將一金屬線，兩端掛上重物後跨過冰塊，發現金屬線會漸漸沉入冰中，金屬線會穿過冰塊，最後可重物會跌到地面，但冰塊卻不會斷開，這便是復冰實驗，這實驗的原理，是重物會使金屬線產生很大的壓力，使冰熔解，金屬線便會沉入冰中，而金屬線下的冰熔解會吸熱，使金屬線上的水重新結冰，復原為冰塊，這便是復冰實驗。可見冰在高壓力下便變成水。其它如滑冰，滑冰鞋的尖刀，對冰塊產生高壓，使冰熔解，因而使摩擦消失，便可以在冰面上滑行。
你問水加壓會變什麼？
答案是什麼也沒變。
每一種物質在某一種條件時，會變成某種狀態，而壓力不是物體態變化的主因(主因是溫度)，壓力可以使物質較易趨向某一種狀態。水在液體時體積是最小，小於固體，更遠小於氣體，加壓後只會令水更難變成氣體或固體。所以在高壓下，水而更低溫下(低於攝氏零度)才可以變成固體，在更高溫度(高於100℃)才可以變成氣體。

海底壓力：
西元一九六０年一月二十三日，美國海軍的小型深海潛水艇Trieste I，在西太平洋靠近關島的馬里亞納海溝海域中，潛航至11034公尺。雖然它在每平方英吋一萬六千磅的高壓下，只不過停留了二十分鐘左右。


由此可知，加大水的壓至大約300個大氣壓力亦無法將水變成固態。

With pressure increases under SAME temperature, water is still in liquid form. Deep sea is a good example to this question. If increasing pressure could change the state of water to solid ice, then our sea would have been frozen to a piece of ice. No doubt, when temperature goes down, it becomes ice that I guess you know it already. It's a miracle in the nature, isnt it? At 4C, water density is the heaviest, so ice float to become an insulator separating the cold weather from contacting the water below the ice and keep the water warm (comparatively) for water life below. Ice is less dense than water because its molecular structure changed which expand it's volume. With the same mass/weight, density decrease with volume. On the other hand, increase pressure on ice without changing the temperature, the ice melts. You can try this by pressing a wire on an ice cube, the wire will go down to the ice.

Same thing happen to ice. Ice changes to different state when pressure increase under same temperature. These different states of ice are called polymorphs.

Ice exhibits a large number of polymorphs converting from one to another when pressure increases (See link below for details)

If you know a little bit of physics, pressure and energy (i.e temperature) play a very important and interrelated role in determine the state of a substance: vapour, liquid or solid. At certain temperature, changing pressure will change its state or vice versa.

Even you dont, by observing around the nature, you will know a lot of the natural laws which scientists begin to ask questions and find the underlying principles and explanations.

You have asked the right question, keep it up.

這是普通常識，水在攝氏4度時密度最大，所以水在加壓後仍然是水。