熱脹冷縮5點5點5dim快速

要知道點解物質會熱，咁系因為物質由粒子組成，粒子間互相撞擊的速度愈快，代表溫度愈高，咁即系話可以得出以下推斷：
物質溫度高－＞粒子速度快　－＞粒子間距離會大　－＞咁物質大小會大
物質溫度低－＞粒子速度慢　－＞粒子間距離會小　－＞咁物質大小會小
但系當水冷卻成冰時，由於冰以六角形開放式的網絡結構排列，使水冷卻成冰時，冰系會脹左，之後再繼續冷卻時，冰大小也會比冷卻前的冰小。

When an object gets hot, the heat energy absorbed by the object causes the kinetic and potential energies of molecules in the object to increase. In so doing, the separation of molecules increased as a result of the increase of potential energy. Since the average distance between molecules now is longer than before, the volume of the object increases. The increase in volume is thus obseved macroscopically as "expansion".

The reverse takes place on cooling. When the object loses heat, the molecular potential energy decreases. Separation between molecules thus decreases. The volume of the object is therefores reduced and which is oberved as "contraction".