El ferrocarril transcontinental (The Transcontinental Railroad)

People today refer to the Midwestern and prairie states as flyover country. During the Civil War, crossing those areas was the biggest obstacle in uniting the East and West Coasts of our divided nation. An act of Congress in 1862 authorized the Central Pacific and the Union Pacific railroad companies to build a railroad that would link the coasts. Seven years later, on May 10, 1869, an overwhelmingly immigrant labor force completed the task when a rail line was join in Promontory, Utah. The states had become united at last.

What has a head, two tails, and shoots across the sky? A comet. Coming from the far edges of the solar system, most comets travel around the Sun, while meteors appear as flashing streaks of light in the night sky. Explore these amazing celestial wonders as they zip through space! This book looks at the difference between comets and meteors and their effects on Earth. The physical characteristics of each are identified in detail. This book won’t come crashing down! It’s filled with fun facts that give additional information on this exciting science topic. This book allows students to use...

¿Dónde buscarías algo que no has visto nunca? ¿Dónde van a parar las cosas que se pierden y son invisibles? Mariú quiere encontrar la paciencia que ha perdido su madre, pero no sabe por dónde empezar a buscar.

Learn about the many things humans can do to get warm when they are too cold. Created in collaboration with the Smithsonian Institution, this STEAM book will ignite a curiosity about STEAM topics through real-world examples. It features a hands-on STEAM challenge that is perfect for makerspaces and that guides students step-by-step through the engineering design process. Make STEAM career connections with career advice from actual Smithsonian employees working in STEAM fields. Perfect for English language learners, this Spanish book builds 1st grade students’ early literacy skills.

La saga de los Bernoulli, una familia burguesa de comerciantes y farmacéuticos, está repleta de fascinantes historias de aventuras migratorias, de desafíos intelectuales y sobre todo de mucha matemática. La época en que se desarrollan los acontecimientos narrados está impregnada de un pensamiento humanista y renovador. El ritmo de desarrollo de la ciencia en esta época se acelera. La solución de problemas científico-técnicos se convierte en asunto de importancia estatal. El dominio de los recursos del nuevo cálculo creaba una sensación de posibilidad de resolución de semejantes...