Learn how different measuring instruments achieve varying levels of precision through this interactive comparison. The least count—the smallest measurement an instrument can detect—determines its accuracy. Vernier calipers measure to 0.01 cm using sliding scales, screw gauges reach 0.001 cm through rotational mechanics, while optical instruments achieve 0.00001 cm precision using light wavelengths. Understanding these differences helps students select appropriate tools for scientific measurements and grasp the relationship between instrument design and measurement capability.