1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Thermodynamics cooking Question

  1. Jan 18, 2007 #1
    1. The problem statement, all variables and given/known data

    A househusband is cooking beef stew for his family in a pan that is (a) uncovered, (b) covered with a light lid, and (c) covered with a heavy lid. For which case will the cooking be the shortest? Why?

    2. Relevant equations



    3. The attempt at a solution

    I dont know where to start with this question. Any help would be appreciated. thanks.
     
  2. jcsd
  3. Jan 18, 2007 #2

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Think of the beef being cooked in water on an element that is at a temperature greater than 100 deg. C.

    What happens to the water? What is the temperature of that phase of water? Which of the three ways would result in that (phase of) water reaching the highest temperature?

    AM
     
  4. Jan 18, 2007 #3
    When the temperature is greater than 100 deg C the water boils and turns into vapor. To get the highest temperature in that phase the pan would need to be covered with a heavy lid. This will give the shortest cooking time.

    Is this correct or am I on the right path? thanks.
     
  5. Jan 18, 2007 #4

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Sort of on the right track. You haven't explained why the heavy lid will give you the shortest cooking time.

    Think of the quantity of heat contained in the steam. You want to maximize the amount of heat contained in the steam. How is that be done (think of the steam as an ideal gas and set up an equation for heat in terms of temperature pressure, volume and quantity of steam)?

    AM
     
  6. Jan 22, 2007 #5
    How does a pressure cooker work?
     
  7. Jan 22, 2007 #6

    Gokul43201

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    But the meat is submerged in the water, isn't it?
     
  8. Jan 23, 2007 #7
    thats a very politically correct problem you have there...
     
  9. Jan 24, 2007 #8

    Andrew Mason

    User Avatar
    Science Advisor
    Homework Helper

    Not necessarily. But it doesn't really matter. Assuming the water and steam are in thermal equilibrium, the water will be at the same temperature as the steam.

    AM
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Thermodynamics cooking Question
Loading...