Heroes y villanos / Heroes and villains

Diamonds and salt are both minerals, but diamonds are more rare than salt. Curious readers will learn what physical and chemical conditions must be present for minerals to form. They'll discover how minerals are identified and how they are used in daily life. Informative and interesting text presents readers with this science content in a fun way. A graphic organizer shows how different minerals are identified and fact boxes provide readers with exciting supplementary information.

"Some things are so huge or so old that it's hard to wrap your mind around them. But what if we took these big, hard-to-imagine objects and events and compared them to things we can see, feel and touch? Instantly, we'd see our world in a whole new way." So begins this endlessly intriguing guide to better understanding all those really big ideas and numbers children come across on a regular basis. Author David J. Smith has found clever devices to scale down everything from time lines (the history of Earth compressed into one year), to quantities (all the wealth in the world divided into one...

Desde el Big Bang hasta tu cumpleaños, y (casi) todo lo demás, este divertido y revelador libro cuenta tu historia. Esta es tu biografía (aunque no lo sepas). Este libro te llevará por un increíble recorrido desde el Big Bang hasta tu nacimiento (¡y en menos de lo que tardas en ponerte los calcetines!). Sus páginas te ayudarán a atravesar océanos de tiempo para ir desde el espacio hasta la puerta de tu casa en una aventura que empieza con un gran BOOM. ¿Te apuntas al viaje de tu vida?

Explains the basics of the most powerful machines around town and describes their major parts and functions, featuring dynamic photographs that will make little ones feel as though they are in the driver's seat.