點解湯圓剛放在碗中是沉的？？？？？？？？？

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Because when density of an object is higher than 1,it will sink in water.

Just like the soap,because of it's density is nearly to1 ,so when you throw the soap in water,it will flow first and sink again gradually.

係咪生存, 未熟既係會沉架.

2008-06-01 17:22:56 補充：
係咪生既, 未熟既係會沉的. (打錯字)