The design of scissors varied as the ages passed. First tools looked like a couple of knives attached together with a springy band of metal. Over time they evolved into a pair of metal edges joined with a pivot rod. Sharp ends are placed facing one another, and when operated - two blades slide along and against each other. The actual separating action depends on two major factor - shearing (which is a major force in lower-quality tools) and cutting (common in higher-quality instruments). These devices can vary in type based on their application - from children`s shears used in schools to hair trimmers and branch cutters.