El experimento Barcelona

Explains the basic science of flight, the problems of getting vehicles into the air, different types of engines, and aircraft design, and includes instructions for making aircraft models.

Young readers may have heard about the benefits of using and making the most of their resources, but how does that factor into an economic discussion? This thorough discussion defines resources and describes the different types of resources and why some divide them into three categories and others choose four. The book also addresses the concept of scarcity, showing readers how, because all resources have their limits, it is important to use them responsibly and efficiently in a healthy economy.

La conjugación alcohol y adolescencia es una preocupación constante que aparece cíclicamente en el interés social. En algunas ocasiones se visibiliza como un problema de orden público, en otros se acentúa como un problema educativo, en otras ocasiones coge fuerza la visión de salud pública. Todas son ciertas, pero parciales e incompletas si no se aúnan todas las visiones en una interpretación más omnicomprensiva del fenómeno del consumo de alcohol juvenil. Ello es especialmente necesario cuando se trata de buscar soluciones o programas preventivos de impacto en la población...

"Simple text and photos present the seasonal weather cycle and activities to do in each season"--Provided by publisher.