Heat transfer between 2 mediums

In summary: Therefore, the silver rod will cool faster.In summary, the conversation discusses heat transfer and its various processes such as conduction, convection, and radiation. The group also explores how different mediums, such as air and water, affect the rate of heat transfer. It is noted that water, with its high specific heat, is more effective in transferring heat compared to other gases. The conversation also touches on the concept of specific heat and how it affects the rate of heat transfer. Additionally, the group explores the difference in cooling rates for two metal rods heated in a fire, with the conclusion that the silver rod, due to its higher specific heat and ability to radiate heat quickly, will cool faster.
  • #1
sgstudent
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Hi guys, I have a question regarding heat transfer. When I have a piece of heated metal which is left to cool down in air, it goes something like this right? Heat is transferred to air by conduction (metal to air) then from air heat is given off by convection currents. Also, radiation occurs. But I was wondering if the heat transfer from metal to air (conduction process) will change if another gas is used. I'm guessing it will have another effect because if water is used instead more heat will be transferred. So does it mean that the denser the covering medium, the faster the heat can escape? So for heat exchanges where hot water is pumped through a metal pipe, if 2 different metals are used will the better conductor metal take away more heat at the transferal part (water to metal). I don't really understand this though.

Also, if I have two pieces of metal rods which is heated in a fire and one becomes red hot and the other remains silver it means that the silver one is hotter at the other end (not in the fire) as the heat is able to transfer to the rest of the parts while the red hot one accumulates the heat at one place so the end will be not as hot as compared to the silver one. But if I were to take both of them out to cool in the same environment, then which one will cool faster? I'm guessing it should be the same as radiation will be the same as the silver one is hot throughout whole the red hot one is extremely hot at one part and cool at the other, so net radiation is equal. So it boils down to conduction through the 2 mediums, so I'm guessing it should be the same too?
Thanks for the help!
 
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  • #2
The rate at which heat is absorbed or given away depends on specific heat. Since water has a high specific heat, it takes in more heat to show a small change in temperature. Any gas can't compete with water.
The rod which is not silverish will radiate the heat quickly(black body radiation). (even though it may not be 'black', it is blacker than the silver rod!).
 

1. How does heat transfer occur between two mediums?

Heat transfer between two mediums occurs through three main mechanisms: conduction, convection, and radiation. In conduction, heat is transferred through direct contact between the two mediums. Convection involves the movement of heated particles within a medium, which then transfers heat to the other medium. Radiation occurs when heat is transferred through electromagnetic waves.

2. What factors affect the rate of heat transfer between two mediums?

The rate of heat transfer between two mediums depends on several factors, including the temperature difference between the two mediums, the thermal conductivity of the materials, and the surface area of contact between the two mediums. Additionally, the presence of insulation or barriers can also affect the rate of heat transfer.

3. Can heat transfer occur between two mediums that are not in direct contact?

Yes, heat transfer can occur between two mediums that are not in direct contact through the process of radiation. This is why we can feel the warmth of the sun even though it is not in direct contact with our skin.

4. How does the direction of heat transfer between two mediums depend on temperature?

The direction of heat transfer between two mediums is always from the hotter medium to the colder one. This is because heat naturally flows from areas of higher temperature to areas of lower temperature in an attempt to reach thermal equilibrium.

5. How can heat transfer between two mediums be controlled?

Heat transfer between two mediums can be controlled through various methods such as insulation, convection barriers, and adjusting the surface area of contact. Additionally, regulating the temperature difference between the two mediums can also affect the rate of heat transfer.

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