Why heat cannot be conducted through vaccum?
Conduction requires a medium. In vacuum there is no medium through which heat can be conducted. However, heat can be transmitted through vacuum in the form of radiation.
It isn't reduced because of conduction, conduction is a way to transfer heat btw a vaccum flask works like this: it has a shiny surface facing the liquid which reflects the heat back into the liquid. if you look at a picture (below is a link) then u'll see that there is vaccum between the inner and the outer container. heat cannot travel in vaccum. also to prevent heat from escaping upwards, we generally use…
it consists a double walled glass vessel having a vaccum between the walls.both these walls are silvered on the vaccum side.no heat can enter or leave the inner flask by convection oor conduction across vaccum.a small amount of heat can be gained by the flask through by radiation but the silver surface to control radiant heat and reduce it to a minimum