Preschool children estimating lengths - the role of standard units as relevant prior knowledge

International audienceLength estimation is a relevant ability in our everyday life. Especially during the Corona Pandemic, estimating a distance of 1.50 m is crucial for our health and social life. Standard units play a central role in many length estimation processes that occur in our everyday surrounding. However, standard units as well as approaches to length estimation are generally discussed with children in elementary school while children already face situations already in their preschool age. This research addresses the question of how preschool children deal with length estimation. In a study with 189 preschool children who were about to start elementary school, we assessed their length estimates and analyzed the role of standard units in this context. It shows that standard units are used by the majority of kids to estimate lengths. However, their estimates are far from precise but the relation between the measures they name is mostly correct