During which stage of cognitive development, as proposed by Piaget, do children typically start to understand the concept of conservation and begin to engage in logical thinking about concrete objects?

According to Piaget, children typically start to understand the concept of conservation during the Concrete Operational Stage, which occurs roughly between the ages of 7 and 11. This stage is important because children begin to think logically about concrete objects and understand that certain properties, like volume or mass, do not change even if their appearance does. For example, if you pour the same amount of water from a short, wide glass into a tall, narrow glass, a child in this stage will understand that the amount of water remains the same, even though it looks different. This ability to mentally manipulate and understand the relationships between objects marks a significant step in their cognitive development. Therefore, during this stage, children become more capable of reasoning and problem-solving in practical situations.