Por qué covid asusta al mundo & Covid está aquí, ¿Y ahora qué?

Explains the basic science of flight, the problems of getting vehicles into the air, different types of engines, and aircraft design, and includes instructions for making aircraft models.

Readers may never expect that they might free fall to Earth, but if they have ever dived into a pool, that's exactly what they've done. This book shows readers how Newton's three laws of motion affect divers, skydivers, and mountain climbers' movements. Readers discover who uses gravity, and who works against it, and all other forces that contribute to a successful dive or climb. After reading this book, readers can decide if they will ever be interested in engaging in one of these extreme sports.

Granpa has given Frederick a gift: a sealed box. It talks and contains all the knowledge of the world. This is the story of Frederick and his box, and many information about nature and ecology. For children 9 and up.

Este libro ofrece información sobre las características físicas, el comportamiento e hábitos de este insecto.