Silica aerogel felt is the best insulation material to date, its pore size is lower than the mean free path of air molecules under normal pressure, so the air molecules in the aerogel pores are almost stationary, thus avoiding the convective heat transfer of air. The extremely low bulk density of the aerogel and the curved path of the nano-network structure also prevent gaseous and solid-state heat conduction, and the "infinite" pore wall tends to minimize heat radiation. These three aspects work together to almost block all the ways of heat transfer, making the aerogel reach the thermal insulation effect unmatched by other materials, even far lower than the thermal conductivity of static air of 0.025w/m.k at