Specific heat capacity of aluminium

[waqasmalik]

Hi all, i have a question regarding specific heat capacity of aluminium. Thermal conductivity of copper is highest among steel,aluminium and copper. If we compare copper and steel then we see that to raise the temperature of one kg of copper to one degree centigrade we need less heat as compared to steel because steel has 1/6 of thermal conductivity as compared to copper, heat will move slowly . Now , if we talk about aluminium then it has its thermal conductivity more than that of steel but less than copper.As a result it must have high specific heat capacity as compared to copper but less than that of steel.If we have a look at technical literature then we see that the specific heat capacity of aluminium is twice of steel. What could be the reason behinde this?

THANX ALL IN ADVANCE

 

[racookpe1978]

Look at the units.

Specific heat capacity is "per unit mass". Al is much lighter than Fe, Cu is between FE and Al.
Al = .91
Cu = .39
Fe = .49

Heat conduction (its transfer ability) is Btu/hr/deg F or Watts/meter/deg C, right?
Al = 205
Brass = 109
Cu = 401
Fe = 43
Stainless Steel = 16

So, conductivity varies very strongly with alloy type, specific heat capacity varies much less. Density varies modestly.

Only if two substances have the same area, the same length, across the same temperature difference can you directly compare the heat transfer coefficients directly.
The same mass of each of the three metals will have different areas.
Same area of the three metals will have different masses.

Its like comparing structural aluminum against structural steel. When weight matters, the "less strong", less stiff, more expensive Al can carry the same loads as the "cheaper" steel because weight, strength, rigidity and price are all three different. When you don't care how much something weighs, or when added weight helps the design, the Al choice seldom works.

 

[waqasmalik]

Yes, thanx racookpee, i didnt notice the mass difference.Aluminium has lighter weight so its one kg mass will have more volume/area as compared to same mass of iron so the specific heat capacity of aluminium is higher as compared to iron.I would ask one more thing.

Had the density of aluminium and iron been the same then could we have claim that the iron would have more specific heat capacity?

 

[waqasmalik]

Also, how Cu is in between Fe and Al? Have a look at densities.

Al=2840kg/m^3
Fe=7870
Cu=8950

So if all of them have same volume then copper will be the heaviest, aluminium will be lightest. Plz correct me if i am wrong