點解0度係冰既溶點又係水既冰點??

It is illogical if the melting point of ice and its freezing point are not the same.
Just imagine what would happen if the melting point is lower than the freezing point. The ice would melt when it reaches the melting point, and as the temperature continues to rise, the ice would reach the freezing point....it freezes again !!! A fact that is hard to conceive in the physical world, and which has never been observed in the real world.
In the physical world, the change of state of water or ice depends on the way heat is transferred. If the ice (the solid state of water) absorbs heat (the latent heat), it changes it state to (liquid) water by increasing its internal energy. On the contrary, if heat is taken out from (liquid) water at the melting/freezing point, it changes into solid water (ice) by decreasing its internal energy.
Therefore, at the melting/freezing point, whether water remains in the solid or liquid state depends on the internal energy possessed by the substance at that moment. Water at zero degree Celsius contains higher internal energy than solid water (ice) at the same temperature.

it is so easy .first you need to know whatis the meaning of 溶點and冰點 溶點=一個object既max temp; 冰點=一個object既min temp,即係好簡單