A spring scale is a device used to measure weight or force. It operates on 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. Spring scales are commonly used in various applications, such as in laboratories, classrooms, and for weighing luggage. They can measure in units like grams or pounds, making them versatile for different needs. Their simple design allows for easy reading and understanding of measurements.