DK 
First How Things Work Encyclopedia 
A First Reference Book for Children

All the most important science topics for kids, from magnets and sound waves to flight and search engines, are simply explained in this fun and informative illustrated STEM book for children studying KS1 and KS2 subjects.
First How Things Work Encyclopedia covers everything children aged 5-9 need to know. What makes rockets go? How does electricity work? Why do we sometimes see rainbows in the sky? This book follows the curriculum for Key Stages 1 and 2 and provides a strong foundation for science and STEM learning through the rest of the school years.
This is the perfect homework help ebook to support children as they begin to learn about the inner workings of the world around them. It introduces exciting areas of science that will get kids hooked on learning about how things work, including levers, light bulbs, engines, and roller-coasters.
This book sits in DK“s popular First Reference series, which is perfect for kids who want to explore the world around them.