Understanding Average Specific Heats in Fluid Mechanics Fundamentals

[mech-eng]

I have been refreshing my fundamentals. Average specific heats are confusing for me. Why they are average? Are there different values for them so the averages are taken? Would you please explain this?

Source: Fluid Mechanics Fundamentals and Applications by Çengel/Boles.
Thank you.

 

[anorlunda]

Sure, many materials have specific heat values that change with temperature. The one above is for diamond.

 

[mech-eng]

How can scientists measure these values? I think it should be very hard process.

Thank you.

 

[Chestermiller]

How can scientists measure these values? I think it should be very hard process.

Thank you.

Read about Joule's experiments.