A thermos flask is a special container used to keep liquids hot or cold for a long period of time. It is commonly used to carry drinks such as tea, coffee, milk, soup, or cold water. Thermos flasks are widely used in homes, schools, offices, and during travel.
A thermos flask works using insulation. It has two walls with a vacuum space between them. The vacuum reduces heat transfer, which helps to maintain the temperature of the liquid inside. Because of this design, hot drinks stay hot and cold drinks stay cold for several hours.
Thermos flasks are usually made from stainless steel, glass, or plastic. Many of them also have a tight lid or stopper that prevents heat from escaping and stops spills. Some lids can also be used as cups for drinking
