壓力鍋與pressure 的關聯

當壓力鍋使用的時候, 內部與外面的 air particles 會怎樣?

The air pressure inside the pressure-cooker is higher than that outside, which is at atmospheric pressure. Generally, the pressure inside a pressure-cooker is set at 107 kPa against a standard atmospheric pressure of 100 kPa. That is, there is a pressure increase of 7 kPa inside the cooker.

pressure 又點產生?

The increase in pressure inside the cooker is due to evapouration of water forming steam in the cooker. The increase in pressure has the effect of raising the boiling point of water inside the cooker to a temperature of around 122'C, hence making heat transfer to the food much faster than an ordinary cooker.

You may also refer to the following web-page for a generaly knowledge of pressure-cooker:

http://en.wikipedia.org/wiki/Pressure_cooker

其實壓力鍋的原理唔係主要係壓力果度....
當壓力鍋加熱時....入面的氣壓會上升(因為增加左分子的平均動能)....當裡面的壓力大於外面某個數值時......壓力鍋的蓋會被打開，以免發生危險。

千其唔好以為壓力鍋係以壓力黎煮熟食物，只係名黎....佢既結構同保温瓶差唔多....壓力鍋主要係節省電力而已。


希望幫到你^^

what happens inside the cooker is that the air particles move in a ripid state due to the increases on temperature. Since the volume is fix by the cooker so we can say increase in temperature leads to the increase in pressure shown by(PV=RT or Pv=nRT) or ( Pv=zRT--> real gas law)
the outside air particles will heat up as well and expand, but since temperature is proportional to volume therefore no pressure increase.