Thermos

    _____                    
   /_____\* --- cover        
  |_\__*/_| --- cap          
 / //   \\ \                 
| | |~~~| | |*--- case       
| | |   | |*| --- glass walls
| | |   | | |  + silvered    
| | |   | | |    surfaces    
| | |   |*| | --- vacuum     
| | |_*_| | | --- liquid     
| |_______| |                
|___________|                

Flask used for keeping liquid at the same temperature for long periods of time. Its design has two bottles placed one within another with a vacuum inbetween. The inner walls are made of glass (nowadays stainless steel) due to its poor conductivity. It was invented in 1892 by Sir James Dewar for scienticic use. Casually, it is used for keeping beverages such as soup or tea warm in cold temperatures, but also has scientific uses, such as holding dangerously high-temperature liquid.


Diagrams: 1, 2

Photos: Closed, Open, Disassembled


Tea