熱的”傳導” 對流 及 輻射的分別?????????????

傳導, 需要經由物體既粒子共振去傳遞熱力,而呢d物體通常係固體既,粒子排列越密越整齊,佢既傳熱能力越高, for example,你攞隻燒烤叉燒野食,隻叉畀火燒,熱力由叉頭傳去叉尾,因為佢係鐵(金屬粒子排烈整齊,又有metallic bond既電子作傳熱作用,所以係高導熱體。手柄木做既,佢係低傳熱體,所以你唔會覺會灼傷

對流, o係流體同氣體中傳熱既方法,當底層既粒子受熱,佢地會振動得好犀利,咁佢既density密度會下降(因為粒子o係樹係咁振係咁互撞,活動空間高左),咁周圍無受熱既粒力,密度大既,就會形成壓力推過去因受熱而密度變低既低壓區,補充走左既受熱粒子,咁受熱既粒子o係升高既過程,佢會傳d熱能畀周圍既粒子,咁升到最高果陣,佢既熱能傳晒畀其他粒子,咪變番冷粒子,密度又會大番,咪向番下沉羅,咁一個升一個沉,就會形成對流作用,風就係咁形成既(呢樹解釋埋風既原理,就好似睇天氣報告入面,你見到d海面有低壓區,其實暖海流既能量不段將海水變成水氣,向上爬升,形成低壓區,咁低壓區周圍既冷空氣又會扯入去填補,不斷重覆,形成颱風)

咁輯射就係經過電磁波既形式黎傳遞熱能,光就係電磁波,x ray又係電磁波,連我地叮野食既微波爐都係電磁波,特性係唔使物質粒子去傳送能量,係直接直線咁射埋你樹,大陽既熱能就係咁傳送過黎既

2009-10-21 01:24:02 補充：
你講既散熱器,佢既功能係想帶走散熱管入面叫雪種既熱力,佢要快d吸走雪種既熱,令雪種可以溫度下降再經壓縮變冷。所以佢既作用係吸熱,之後再散熱!

但係燃料儲存庫用銀白色,係因為佢要低溫度,佢本身溫度唔可以高,所以要吸熱慢,設計果陣係先考慮佢吸熱慢呢個特點,可以保持低溫羅

傳導：是指物質與物質之間接觸到，然後熱會由高走向低。

黑色物體吸熱多，散熱也多。白色則相反。這是因為黑色吸收大部份的輻射

所以我們看到物體是黑色的，它只反射一小部份光線過來。

對流是指空氣的帶熱流動，冷空氣向下，熱空氣向上是因為，冷空氣的粒子

沒有怎麼活潑，而熱空氣則比較活潑，那麼熱空氣的密度便低一點，所以

便會向上浮。冷空氣則向下。

燃料儲存庫用銀色是因為銀色吸熱慢，散熱慢，如果發生火災或爆炸便能起

到隔熱的功效。

還有一個問題...汽車上的引擎散熱器是黑色的因為吸熱快 散熱快...但吸熱快不是令到"散熱器"更熱嗎?
The colour of the cooling system only affects heat loss by radiation. In fact, heat loss in this case is mainly by "forced convection" in which the movement of air onto the engine surface is far more important.

而"燃料儲存庫"卻用銀白色 吸熱慢 散熱慢
如果散熱慢的話 為什麼不會有危險?
If the rate of absorption of heat is low by using a shiny surface, the temperature rsie of the fuel tank is also low. This could keep the equilibrium temperature within a safe range.
In case a dull black surface is used on the fuel tank, the equilibrium temperature so attained would be higher than if a shimy surface is used.

如對流似的...為什麼冷空氣向下熱空氣向上...然後又不停上上下下咁動...密度又跟這些有什麼關係??
In generally, fluids (liquids and gases) with lower density will rise and those with higher density will sink (for reasons, please refer to Archimedeus Principle).
Hot fluid has a density lower than cool fluid, hence hot fluid rises and the surrounding cool fluid will move in to fill up the place previously occupied by the hot fluid. The rising hot fluid would finally be cooled down and sink again, thus setting up a convection current.

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