Illustration of convection currents

[Maxo]

When convection currents are illustrated they are often painted as arrows with red and blue color, the red one being the direction of warmer currents and the blue ones being the direction of cooler currents. See for example this picture:

But how does this go together with the fact that heat is defined as always going from parts of higher temperature to parts of lower temperature? Wouldn't that only be the red arrows then? Does that mean that the currents represented by blue arrows doesn't actually exist?

 

[A.T.]

You are confusing movement of air with transport of heat within air.

 

[Maxo]

You are confusing movement of air with transport of heat within air.

Ok, but wouldn't the transport of heat within air be in the same direction as the red arrows?

 

[olivermsun]

No, the molecular diffusion of heat will be from warm toward cold, or opposite to the direction of the (convection) arrows.

 

[A.T.]

Ok, but wouldn't the transport of heat within air be in the same direction as the red arrows?

At some points, but it can also be in the opposite direction or perpendicular to it.

 

[Maxo]

When talking about transport of heat within air, is that referring to radiation?

 

[A.T.]

When talking about transport of heat within air, is that referring to radiation?

No, diffusion.

 

[Maxo]

No, diffusion.

Is diffusion the same as conduction?

 

[A.T.]

Is diffusion the same as conduction?

Yes:
http://en.wikipedia.org/wiki/Heat_transfer