El mundo de la tecnología: Los inventos del siglo XX (Tech World: 20th Century Inventions)

What causes sound? How does sound travel? Sound begins when matter vibrates. Without this vibration sound could not move and nothing would make any noise. Starting with tiny molecules, this book explains the main concepts of sound and furthers understanding through a series of easy-to-do experiments that will appeal to readers of all ages.

Mariana the the sea turtle and her fellow hatchlings have an adventure on their first trip to the ocean.

GRADES PK–2: This 16-page Spanish title (8'' x 8'') introduces early readers to the leopard—what they eat, why they climb trees, and how far they can jump! FEATURES: Simple Spanish text and vivid photos present fascinating facts about an amazing African animal. Comprehension questions are included to advance learning. EARLY BILINGUAL LITERACY: Help young learners strengthen their bilingual skills—add the English version of this title into your collection, too. BUILD A LIBRARY: Collect every title from the collection to stock your home or classroom library. Reading together is a great...

Todo el mundo habla del cambio climático, pero ¿es verdad todo lo que dicen sobre él? Palmeras en el Polo Norte nos responde a algunas preguntas que todos nos hacemos: ¿cómo está cambiando nuestro entorno? ¿A quién le va a afectar esa transformación y por qué? Este libro habla de la contaminación, de devastadores huracanes, de animales extinguidos y de osos polares; también de volcanes, icebergs, mamuts y científicos que pasan mucho frío; en definitiva, de un fenómeno que nos afecta a todos y de lo que estamos a tiempo de hacer por nuestro planeta.