How do vacuum flasks keep hot liquids hot and cold ones cold? – Cheeki

We’ve got 99 problems and maintaining the temperature of liquids is one of them. Thank James Dewar (inventor of vacuum flasks) that we have a way of keeping our liquids at a desired temperature using vacuum flasks. You can think of a vacuum flask as a water bottle holding another bottle inside it but is separated by va.
You can think of a vacuum flask as a water bottle holding another bottle inside it but is separated by vacuum, with a supporting stand at the bottom. This basic structure provides thermal insulation or reduction of heat transfer. 

Vacuum flask keep hot and cold 1 L

Drinkware Accessories Thermoses Stopper Universal Water Bottle Lid - 45mm Vacuum - Aliexpress

Stanley 470ml Flask – Kokako Organic Coffee Roasters

How do vacuum flasks keep hot liquids hot and cold ones cold? – Cheeki

Sursip 128 oz Insulated Water Jug with Straw Lid, One Gallon Large Vacuum Double Wall Stainless Steel Water Bottle with Handle, Keep Hot & Cold Drinks, Great for Outdoor Sports/Travel/Camping (Black)

GreEco Double Wall Vacuum Flask, Insulated 18/8 Stainless Steel Water Bottle, Hydration Bottle, 32 OZ, Light Blue: Home & Kitchen

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Why does a liquid remain hot or cold for a long time inside a thermos flask? - Quora

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