How tall are towers? Who cleans the window of the Burj Khalifa? Find out more about skyscrapers and the science of tall towers. Do You Know? is a series of levelled non-fiction books featuring video content, project work and critical-thinking activities to motivate and engage young learners. Covering a range of STEM topics from nocturnal animals to climate change, Do You Know? takes an enquiry-based approach, developing children's language, communication and investigation skills. PreK-Grade 1. Paperback.