“At 11:35 p.m., as Radio Armero played cheerful music, a towering wave of mud and rocks bulldozed through the village, roaring like a squadron of fighter jets.” Twenty-three thousand people died in the 1985 eruption of Colombia’s Nevado del Ruiz. To
Dr. Merlin Tuttle and his colleagues at Bat Conservation International aren't scared of bats. These bat crusaders are fascinated by them, with good reason. Bats fly the night skies in nearly every part of the world, but they are the least studied of all m
![Cambridge IGCSE Physics – Duncan, Tom [SRG]](https://cdn.pdfdrive.com/assets/thumbs/9bc/9bc913c169f0db09630a0efc47712189-s.jpg "Cambridge IGCSE Physics – Duncan, Tom [SRG]")
