A Thermos is a vacuum-insulated container designed to keep liquids hot or cold for extended periods. It works by creating a space between two walls that minimizes heat transfer, preventing the contents from losing or gaining temperature. This makes it ideal for beverages like coffee, tea, or cold drinks. Invented in 1892 by Sir James Dewar, the Thermos has become a popular choice for outdoor activities, travel, and everyday use. Available in various sizes and designs, it is made from materials like stainless steel or glass, ensuring durability and ease of cleaning.