Hygroscopic materials are substances that can absorb moisture from the air. This property allows them to attract and hold water vapor, which can lead to changes in their physical state or properties. Common examples of hygroscopic materials include salt, sugar, and certain types of wood. These materials are often used in various applications, such as in desiccants to control humidity or in food preservation to maintain freshness. Understanding hygroscopicity is important in fields like pharmaceuticals and construction, where moisture control is crucial for product stability and structural integrity.