Agujeros negros (Black Holes)

For many years, people believed there were nine planets that orbited the sun. Now we say there are eight. What happened to the ninth planet, Pluto? What are the different planets like? What exactly makes a planet a planet? These are the many intriguing questions answered with this high-interest book, crafted to be accessible for readers of all levels. Young astronomers will be especially fascinated by the stunning photographs and the "Make the Grade" fact boxes.

La Semana Trágica, las huelgas, las luchas y la necesidad del sufragio femenino, las políticas de la infancia en una trama social en gestación, las prisiones, los trasfondos multicolor del yrigoyenismo, la epidemia de gripe, los recovecos del arte: todo pasa por Katherine Sophie Dreier, singular y generosa mujer de vanguardia, a través de una lente estadounidense convertida en audaz caleidoscopio, lo que hace de este libro un relato fascinante del viaje que esta singular mujer emprendiera por Argentina entre 1918 y 1919.

Worksheets designed for use in Spanish immersion classrooms, as a supplement for parents to use with their children for extra practice, or for use by any classroom teacher who wishes to incorporate Spanish instruction in the classroom in the curriculum areas of language arts, math, social studies, and science.

Un cuento con puzles magnéticos y 20 imanes de animales. ¿Qué ocurre si no le das a cada animal su comida? ¡Pues que toda la granja se vuelve loca! Lee el cuento y luego utiliza los imanes para crear tus propias sorpresas en la granja. ¡Hay hasta 100 combinaciones posibles!

California became a territory in the United States when the Treaty of Guadalupe Hidalgo was signed in 1848. That treaty ended the Mexican War. Several days before its signing, gold was discovered at Sutter’s Mill in what is now Sacramento. The non-Native population of the territory was less than one thousand in 1848, but the gold rush increased that number to one hundred thousand by the end of 1849. The gold rush not only made many people wealthy, it brought ecologic devastation while speeding up California’s statehood. This book richly explores this interesting history.