A strain gauge is a device used to measure the amount of deformation or strain in an object when it is subjected to stress. It typically consists of a thin wire or foil arranged in a grid pattern, which changes its electrical resistance when stretched or compressed. This change in resistance can be measured and converted into a precise measurement of strain. Strain gauges are commonly used in various applications, including structural engineering, aerospace, and mechanical testing. They help engineers and scientists monitor the performance of materials and structures, ensuring safety and reliability in designs. Their ability to provide accurate data makes them essential in fields like civil engineering and materials science.