At what developmental stage do children typically begin to understand the concept of conservation?

Children typically begin to understand the concept of conservation during the concrete operational stage, which generally occurs between the ages of 7 and 11 years. This is when they start to grasp that certain properties of objects, such as volume, mass, and number, remain the same even when their shape or arrangement changes. For example, a child understands that pouring water from a short, wide glass into a tall, thin one does not change the amount of water, demonstrating an understanding of conservation of volume.

During this stage, children's thinking becomes more logical and organized, although it is still tied to concrete objects rather than abstract concepts. This is a significant developmental milestone that displays their ability to think systematically about transformations and to follow rules regarding physical objects.

In contrast, during the preoperational stage—which typically spans ages 2 to 7—children lack this understanding and may think that changing an object's appearance changes its quantity. The formal operational stage follows concrete operations and involves abstract thinking, so conservation concepts are established prior to this stage. The sensorimotor stage is an earlier phase, where children are focused on sensory experiences and motor actions, not yet engaging in logical thinking about physical properties.