The field of science. The teaching of knowing frogs is the process of knowing tadpoles evolving into frogs. Children observe tadpoles, grow their front legs and hind legs, shorten their tails, and finally become frogs. Guide children to observe the process of tadpoles' great transformation and explore how to eventually become frogs, so that children can learn to observe and take care of them. Tadpoles cultivate children's patience and care, which belongs to the exploration in the field of science.