磁石的磁力會唔會用盡？

磁石的磁力會唔會用盡？
Magnetic field exist around Magnet is due to the atom arrangement in the Magnet. As long as the arrangement is not changed. The Magnetic force won't be use up.

遮係如果有兩個磁石，放在一齊，而兩個磁石對住的都係S或N極，咁就會反彈啦，如果我唔比佢反彈，擺兩塊板固定呢兩個磁石的位置，咁樣呢兩個磁石會唔會永遠都有磁力？
Permanent Magnet will not weaken in this way.

再簡單點啦，遮係話磁石係唔係在任何環境都可以永久有磁力，而且磁力唔會減弱？
The statement is false as under certain condition, the magnet can be demagnetized such as heat it, put it in an alternating magnetic field or hammer it.

2008-11-30 00:43:56 補充：
咁我想問，如果現時的天氣係3X度，長期放在陽光下會唔會無左磁力？ No.

可唔可以講明係幾多溫度先會無左磁性？ Over 700°C

如果個磁石好大個，係唔係要更高的溫度先會無左磁性？ No. Same temperture no matter how large it is.

如果把一個好大的磁石放在沙漠等的炎熱地區，放14-15個小時，長期被陽光曬住，會唔會無左磁力？ Desert is cold compare with 700°C

有無方咩方法簡單又唔浪費金錢的方法，令磁石即使受熱，都唔會無左磁力或唔會影響得咁大？ No need to do it.

2008-11-30 18:57:56 補充：
如果把一個好大的磁石放在沙漠等的炎熱地區，放14-15個小時，長期被陽光曬住，會唔會無左磁力？ Desert is cold compare with 700°C . However, the heat can accumulate in the Magnet if there is a heat source (sunlight), the temperature can reach a few hundred degree. So, the magnet COULD be weaken.

2008-11-30 18:58:18 補充：
Avoid direct sunlight. Without sunlight, the heat lost through the air can keep the magnet temperature low.
Methods:
1. Cover the magnet with sand, as thick as possible.
2. Cover the magent with Cloth. If you can keep it wet, it can garantee the temperature below 100*C.

Yes, the magnetic field of a permanent magnet will loss gradually. The ordered magnetic (bipolar) specimens will become disordered, according to the 2nd law of thermodynamic. Like the sun will burn out one day.

會架，磁石受熱或受到撞擊會消失磁性。