Hardness testing is a method used to determine the resistance of a material to deformation, particularly permanent indentation. This process helps assess the durability and strength of materials like metals, plastics, and ceramics. Common techniques include the Brinell, Rockwell, and Vickers tests, each using different scales and indenters to measure hardness. The results from hardness testing can guide engineers and manufacturers in selecting appropriate materials for specific applications. For instance, a harder material may be preferred for tools and machinery, while softer materials might be suitable for applications requiring flexibility. Understanding hardness helps ensure the reliability and performance of products.