boiling increase increase ANSWERS The venting of steam of steam venting The the cooking from prevents vessel the temperature to continuing from increase. Because the rate of Because the rate chemical reactions that cause the will of food cooking double with every in 10 °C increase temperature. The boiling point The also of water so that increases, at a is cooked food higher temperature than 100 °C. 1 2 3 chemical useful faster faster pressure direct direct pot food food ing will occur roughly 4 times faster in ing will occur roughly 4 times faster higher ical reactions in the food, and the rate ical reactions in the QUESTIONS How does How temperature inside a stabilise cooker? pressure What happens What inside a pressure when cooker the pressure increases? Why is the cooking cooking is the Why time 4 times faster if the cooking is just temperature 20°C higher than the normal boiling point of water? re. Once the operating pressure is attained, the operating pressure re. Once A ...... B ...... C ...... A B C change pressure pressure and answers. questions Match Pressure cookers operate above atmospheric above atmospheric cookers operate Pressure is raised by only 20 °C above If the temperature 3
(Taken from http://wiki.answers.com/Q/How_does_a_pressure_ http://wiki.answers.com/Q/How_does_a_pressure_ from (Taken cooker_work) pressu stabilises at the boiling in the pot the temperature about which is water at that pressure, point for atmospheres of pressure. Further tem- °C at 2 120 prevented since the pressure is perature increase is of steam from the cooking stabilized by the venting vessel. open pot boiling, why is the cooking time so open pot boiling, answer is that cooking results much faster? The from chem reactions occur depends on at which all chemical temperature dependence of the temperature. The of thumb is reactions is variable, but a rough rule °C increase 10 that the rate will double for every that occur in temperature. Therefore the reactions during cook a pressure cooker at 120 °C, and the food will cook in one quarter of the time.
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T T T T . When . When ...... pressure pressure in the boiling point and increase the and increase ...... point of water point of water ...... SHENGLI cooker is a very is a very cooker reactions in food work faster. faster. work in food reactions cook faster. This is possible is possible This faster. cook ICS IN ICS ...... YS PH Water boiling in a pot with no lid Water Steam has less heat potential heat potential less has Steam the boiling cannot increase Pressure Temperature and pressure are are and pressure Temperature ......
True or false? True when you use a pressure cooker. use a pressure when you For this reason food cooks cooks food this reason For temperature the pressure will will the pressure temperature makes the the makes increase, and the higher temperature makes the makes and the higher temperature increase, because of a ...... cooking instrument, because it makes because it makes instrument, cooking ...... of water due to higher due to of water proportional. because pressure and temperature are are and temperature because pressure b. c. d. you close a you Complete.
In the pressure cooker the pressure develops in- In the pressure cooker the pressure EXCERCISES How does a pressure cooker work? cooker does a pressure How ture will never go over 100 °C because of evapo- over 100 ture will never go 1 2 A
a. side the vessel as time goes on. As pressure increas- side the vessel as time goes on. As pressure increases. Thees the boiling point of the water also of the highfood inside is cooked very fast because the food is notboiling temperature, which means that cooked at 100 °C but at a much higher temperature. ration. Also the vaporised steam is at the same tem- ration. Also the vaporised you cook So when water. perature as the boiling but this time with a sealed cap,with a pot of water temperature, all that will happenas you increase the will try to escape but, because itis that the vapour environment, it will not be ableis inside a sealed in the build up of pressure. Theto escape resulting have a directly propor- temperature and pressure so as one increases so does thetional relationship, six times the heat potential Steam also has other. when it condenses on a cold food product. To know how a pressure cooker works you must a pressure cooker know how To ofit. The boiling point physics behind know the with water in a pot °C. When boiling water is 100 you heat it, the temper- matter how much no lid, no a a temperature exceed will never of 100 °C. when it condenses. point of water. indirectly proportion. proportion. indirectly J;HCE:?D7C?973 I passaggi di stato