tell me why some laptops give very much heat as they are worked on .Is there any logic of speed and power.

if u place a laptop on some soft surface like bed sofa etc it produce a lot of heat because of no area for the air compressor to release heat

as like the cpu the laptop too have an internal fan when it rotates the heated air inside gets blocked when you put in any soft materials like in bed sofa etc as it blocks the air inside only so the laptop gets heated

How can be this avoided to prevent the heating of the Laptop..