chemical change or physical change?

吾知點解我IS呀sir都問我呢條問題xd,呢條問題真係公說公有理,婆說婆有理.我IS呀sir個陣叫我地舉手揀,我舉左physical change架
上一位,如果我斬左你個頭落黎,你個頭有無得回愎番之前咁?!吾通我斬你個過程就係chemical change咩...你個理由真係牽強到無朋友

將1隻雞蛋煮熟,
應該系化學變化
因為將雞蛋煮熟是一個不可能回愎的過程,雞蛋熟了是不能令它回愎生蛋的

2008-04-26 13:58:55 補充：
Forgot to mention Chemical change has to undergo a chemical reaction.

Heating up an egg is a chemical reaction, whereas chopping off ones' head is not.
The same case as chopping wood, you are changing it into another shape, not changing it into another substance.

錯左記住話我知