What materials are thermoses made of? Why?

Question

Thanks!!

Answer 1

The original Thermos was based on the DeWar Flask
http://en.wikipedia.org/wiki/Vacuum_flask
which was created to hold very cold liquid gases so they would not boil off so quickly. The DeWar Flask is a large glass bottle blown by a scientific glassblower with an inside shape sucked back inside so a uniform gap is between the glass walls. The space inside the gap is silvered and a vacuum pulled in the space. The vacuum prevents convection and conduction losses and the silvering prevents radiation losses. Usually the flask is housed in a metal can to protect the metal.
A thermo with a vacuum bottle is made just the same.
With modern materials, it has become possible to use high quality insulation or rigid foams that will withstand a vacuum to provide insulation without the fragility of glass, so they are now made with plastic liners in many cases.

Answer 2

All kinds. My favorite, stainless steel, double walled with a vacuum in between. Cheaper ones are plastic shells with foam insulation. They are almost always and outer shell, and the inner chamber, where the fluid will be. In between it can be just air, or a vacuum, or even different types of foam. This is used to insulate the inner chamber, keeping it warm or cold.

Answer 3

You get thermos flasks made of stainless steel too.