Insulators?

Question

what are the factors that lead to low thermal conductivity , hence insulation ??

Answer 1

Vacuum is a good insulator since conduction and convection are absent and highly silvered surfaces prevent radiative transfer also to a large extent.

Air is a poor conductor compared to a liquid or a solid since the density and hence the number of molecules available for heat transfer are less. So, most of the insulators like thermocole, refractory bricks etc. depend on a high amount of porosity for achieving insulation properties.

In a solid, thermal and electrical conduction depends on the free electrons (electron cloud). Non-metals and ceramics are poor conductors of heat compared to metals.

Answer 2

An insulator is a coating that keeps warmth in like a flask keeps you tea hot and double glassed windows keep the warmth in .