Question

How does conventional oven cooking different from boiling cooking in respect of conduction, convection, and radiation of heart transfer

Answer 1

Let us consider boiling of an potato.

In conventional heating, the heat from the stove has to pass through the vessel, the water and then to the potato. This process involves conduction between the vessel, water and potato. If the vessel is stirred, convection heat transfer is also taking place. If the temperature of the system becomes too high, some amount of heat is also lost to the surroundings in the form of radiation. You may feel hot while standing near the vessel due to this. This process is quite inefficient since the heat has to pass through different stages to reach the potato and takes a longer time to boil the potato. This may also result in the outside being cooked very well whereas the inside is still raw.

In conventional oven, the modes of heat transfer of convection and radiation do not play a role. This is because there is no flow of fluid inside the oven and since the system is closed, there is no transfer of energy in the form of radiation to the outside surroundings. Electrical energy is converted to heat energy which penetrates through the vessel, water and potato and boils it. Therefore, much of the cooking is through conduction alone and not much energy is lost unecessarily as radiation. This makes the process of cooking faster.