Soy bueno para las matemáticas

There are many kinds of friends including invisible ones, family members, pets, pen pals you have never met, and best friends. This book celebrates the special bond in all its diversity.

Many children have heard of dams, but not many know what they are. This book engages young readers as it reveals the many fascinating aspects of the worlds largest dam, which was built on the border of Paraguay and Brazil.

Defines pulleys, explains their functions, and suggests simple experiments to demonstrate how they work.

The world is filled with curious objects made by plants, animals, and even by the Earth itself. Dive into this collection of more than 100 intriguing items from the natural world and discover the stories behind them. Learn how huge whales eat tiny animals from looking at their bristly teeth, why butterflies shine and glitter in the sunlight from seeing their minute wing scales, how plants transport water and food around from examining a delicate leaf skeleton, and what makes every snowflake unique from admiring their miniature, branching crystals of ice. Birds' eggs, a lump of coal, a glass...