# Simple heat question

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Hello everyone,

When looking at specific heat capacity and thermal conductivity, is a higher number better?

Im pretty sure I already understand how each number works, but someone told me otherwise and now I'm less sure about myself.

Am I correct in thinking that the higher the numbers, the better?

If this is the case, what's an example of a very high heat capacity, and a very low one. Also for thermal conductivity, what is a very high number and which is a very low number.

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I think you should explain what you mean by saying "better". Conductivity and heat capacity can serve different purposes.

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6 minutes ago, Gracefulmuse said:

Am I correct in thinking that the higher the numbers, the better?

That depends on your definition of "better". If you want to build an insulated door, you should go for gold amalgam because it has the lowest thermal conductivity. If you want the door to transfer heat as fast as possible while closed, you should go for the highest thermal conductivity.

Simply put, thermal conductivity tells how fast the element will transfer heat while capacity tells how much energy it takes to heat up one kg one C. This means if you want to transfer a lot of heat (positive or negative), you want a high thermal capacity.

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Water has a high heat capacity. That means it is slow to heat up and slow to cool down. A room filled with hot water takes a LOT of effort to cool down. Phosphorous has a low heat capacity. That means it takes very little effort to heat it up or cool it down.

Conductivity is the opposite of insulation. Metal tiles have high conductivity, that means heat energy will zip right through them. Insulated tiles have low conductivity, it takes ages for heat to go through.

They're different concepts and have different uses.

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High thermal capacity means it heats and cools down up slower. Holds more heat inside of itself. Water has higher heat capacity than oil so using it as a coolant for the smelter makes it heat up less than oil would.

High thermal conductivity means it transfers heat with stuff around it faster. Iron walls will spread the heat around fast while ceramic walls very slow.

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I apologize for the confusion with the word "Better", English is not my first language.

I understand perfectly now.

Thank you all for your help.