The Thermos Flask as we know it today was first produced in 1904 and it quickly became a staple product in the lives of adventurers, explorers, and everyday people like us. Thermos Flasks are especially useful for picnics, lunches at work and for those who like outdoor pastimes to enable them to carry around hot or cold drinks.
While we generally use them to keep our drinks hot, vacuum flasks were invented by James Dewar in 1892 to keep things very cold.
Dewar invented the vacuum flask to preserve liquefied gases by preventing the transfer of heat from the surroundings to the liquid. The vacuum space between the walls (which are ordinarily glass or steel) is practically a non-conductor of heat.
It started out being called a Vacuum flask, a Thermos flask and also a Dewar Vessel, as it was invented by the British chemist and physicist Sir James Dewar. It was a basic vessel with double walls, the space between which is a vacuum and protected by a metal casing.