Straining is a process of separating solid particles from a liquid or gas. It is commonly used in cooking, where it is used to separate solids from liquids such as when making stocks or sauces. It can also be used to filter out impurities from water or other liquids. Strainers are often used in industrial processes to remove unwanted particles from a mixture. Strainers can also be used to separate different types of materials, such as separating sand from gravel.