Mamá, papá ¡Por favor enséñame!

If a person were ever face-to-face with a huge, hungry animal with sharp teeth, they probably wouldn’t care exactly what that animal was! But from a safe location, can we tell whether it was a crocodile or alligator that wanted to take a bite? By examining their jaw structure, teeth, and other physical features, we can easily tell these two animals apart! Graphic organizers and amazing images highlight each animal’s habitat and other small differences between the two fearsome creatures, showing readers just what creature is lurking below the waters.

It was September 14, 1814, and America and Great Britain were at war. Frances Scott Key watched from the deck of a British ship, where he was being held captive, as cannons exploded around them. After 25 hours, the fighting ceased and Key peered through the clearing smoke, looking for some sign as to the outcome of the battle. Was the American flag still flying? His wartime experience inspired Key to write a poem, which was later set to music and became America’s national anthem. This book tells the story of the inspiration behind our national anthem, which helped transform the flag into a...

Esta cuarta edición expone los fundamentos de las señales y sistemas discretos en el tiempo y procesamiento digital de señales. Este texto es adecuado para estudiantes de Ingeniería eléctrica, ingeniería informática y Ciencia de la computación.

In this book, children learn how we can tell if something is shiny or dull and which materials have these properties.