Do fish sleep? How do cats see in the dark? Day and night are two different worlds to a child and this book explains both of them with lively text, colorful illustrations and imaginative activities. Included About the Explore Your World -- a captivating interactive series for young explorers. This new series covers a wide variety of science, nature and technology topics in an innovative and interactive way. The books make use of a profusion of engaging line drawings and colorful illustrations along with delightful pullouts, pop-ups, fold-outs, transparency overlays, reveal wheels, books-within-books and more. Each page offers a surprise for young, curious readers. Lively captions featuring non-technical explanations accompany all the illustrations.