This lesson plan aims to teach preschool pupils to identify and differentiate between big and small animals. The plan involves showing pictures of various animals like elephants, horses, dogs and asking the children to name and categorize them by size. Activities include having the children separate pictures of big and small animals into two columns and matching big animal pictures to a chart with small animals. The lesson evaluates the children by having them draw lines connecting big and small animals and assigns them to color pictures to further practice the size differentiation.