Piaget's Stage 3 of Cognitive Development

Piaget's third stage of cognitive development, the concrete operational stage, lasts from 7 to 11 years of age. In this stage, children develop logical thinking skills related to concrete or real-world events.

Children develop an understanding of conservation, understanding that an object's mass, volume, and number remain constant despite changes in shape. For example, a child understands that reshaping a piece of Play-Doh doesn't change its quantity.

They further develop the idea of reversibility, or the ability to reverse actions mentally. This is evident when they realize that pouring water into a differently shaped container doesn't change its volume. They also recognize that mathematical operations, like addition and subtraction or multiplication and division, are reversible.

At this stage, children also learn the concept of classification, which involves classifying items into various sets or subsets and understanding their interrelations.

For example, a 10-year-old with a baseball card collection might organize the cards by a player's position, team, or statistics.