A spring scale is a device used to measure weight or force. It operates on the principle of Hooke's Law, which states that the force exerted by a spring is directly proportional to its extension or compression. When an object is hung from the scale, the spring stretches, and the amount of stretch indicates the weight of the object. These scales are commonly used in various applications, including education, laboratories, and industries. They can measure forces in units such as newtons or pounds. Spring scales are simple, affordable, and provide a quick way to gauge weight without the need for complex electronics.