Lions

A scientific look at the natural processes that create waterfalls, and where they are likely to form.

The use of calendars dates back thousands of years. Why are we driven to record time, and what would happen if we did not? Who created the concept of calendars? Why do different cultures use different calendar systems? And why are calendars so important to us? It is about "time" we found out! Created in collaboration with the Smithsonian Institution, this Spanish-translated Smithsonian Informational Text builds reading skills while engaging students' curiosity about STEAM topics through real-world examples. Packed with factoids and informative sidebars, it features a hands-on STEAM challenge...

Introduces the concept of heat, how it's created, how it affects materials around it, and how heat is used.

¿Sientes que últimamente se te olvidan las cosas o que no puedes recordar los nombres? ¿Te cuesta a veces encontrar las palabras correctas para expresarte? No te preocupes, este libro es perfecto para ti. Con el paso de los años comienza a decaer el rendimiento físico e intelectual; es la evolución normal de toda persona. Sin embargo, no tienes por qué resignarte: igual que al ejercitar el cuerpo combatimos el envejecimiento físico, al entrenar nuestra mente rejuvenecemos el cerebro y fortalecemos sus funciones. Gracias a los sencillos ejercicios que contiene este libro, preparados...