Almost every child owns a cup magnifier. But how can we ensure that children and their families use it more thoughtfully? The authors - both mothers and educators - have succeeded in telling an impressive story about the earthworm Rudi with little text and without a condescending tone, which is exciting until the end and has a happy conclusion. They know how to raise awareness about the use of the cup magnifier. So that no animals are ever forgotten in the cup magnifier again!.