為什麼物體遇熱會熔化?

Melting is, in fact, a state transition. It is a physical process by which a substance changes its state from solid to liquid.

In the microscopic theory, substances conatin molecules which are held together by an intermolecular attractive force. When a substance is heated, its molecules acquire energy, hence their vibrational motion increases and at the same time they have got sufficient energy to overcome the intermolecular attractive force. As a result, separation between these molecules increases. This explains why for most substances, they increase in volume on heating.

When the energy possessed by the molecules are strong enough to break the intermolecular attractive force to a certain extent and become free to move. The free motion of these molecules is observed macroscopically that the substance has become a liquid.

Certain substances undergo "sublimation". They change to the gas state directly from the solid state on heating, without transiting through the liquide state. A common example is carbon dioxide, the solid state of which (dry ice) changes to gaseous carbon dioxide at room temperature. Another example is iodine, which also undergoes sublimation on heating.

001你是白癡嗎?空氣是由多種元素所構成的.而它們都已經是氣態.當然不會熔化啦...

物質有很多種狀態.液態.固態.氣態.等離子態.電"獎"態.等等.

而所謂的熔化.就是從固態走向液態的步驟.就是冰熔化為水.同一樣的物質.只是所擁有的能量不同.而以不同的狀態存在而已.

固態的物質到達臨介點便會熔化為液態.再來就是氣化為氣態.而其他狀態剛需要其他特定條件.而臨介點是根據物質與氣壓的不同有所變化的.


而任何物質都會熔化的.而熔化跟燃燒是兩回事來的.別被小白所誤導.熔化跟壓力有關.(而壓力亦跟重力有關)

如水.在常溫與及正常地球氣壓下是液態.但在同樣溫度之下.大氣壓力有所加強.臨介點的溫度亦會不同.