About the Author

Jordi Maz�n is a professor and researcher in the applied physics department at the Polytechnic University of Catalonia. He is the author of a dozen books, including 100 preguntas de f�sica: �Por qu� vuelan los aviones de papel, y por qu� vuelan los de verdad? and Conocer las nubes. Raquel Gu is a cartoonist, an illustrator, and a translator. She is the author and illustrator of Peque�os Granujas and Tengo diabetes, �te lo cuento? and the illustrator of Mati y sus mateaventuras.