Newton's Laws: A Fairy Tale [PDF + eBook + worksheet]

A 123-page illustrated fairy tale that teaches Newton's three laws of motion through the adventures of Kip, a curious boy with nothing but an apple to his name, and Newton, an eccentric wizard who keeps figuring out how the universe works by accident. Along with rival wizard Leibniz, the contested heir Prince Eric, and a guard captain very devoted to him, they discover the laws of motion together — and (mostly) save the kingdom.

Written by Sarah Allen, illustrated in full color by Sheila Stephanie Elizan. For ages 9–12.

What's inside the book

• Four chapters of fairy tale (roughly the first 75 pages), where Kip and Newton discover the three laws of motion in the wild — by tumbling over cliffs, picking up rocks on the road, arguing with rival wizard Leibniz, and climbing a tower that won't stop swaying in the wind.
• "A Note from the Librarian" sidebars throughout the story that connect each plot moment to the real physics: Newton's three laws, friction, the normal force, weight vs. mass, velocity vs. acceleration, with brief tastes of entropy and calculus.
• "Try to Break the Law!" hands-on experiments woven into the text — things kids can try with a rolling chair, a wall, a friend, a sock.
• Five practice sections in the back:
  • A worked free-body-diagram example told as a story (Newton's tippy tower)
  • Five free-body-diagram problems to draw (unicorn, troll, pirate, dragon, dragon-in-dive)
  • F=ma setup practice with friction
  • A creative writing prompt — "you've been appointed the official bard of the land of fairy tale physics" — write your own physics story about Newton's Second Law
  • Riddles in the Woods with the Trickster Fairy, on identifying third-law force pairs
• A vocabulary glossary at the end covering force, perpendicular, normal, weight, mass, velocity, and acceleration in plain language.

Plus a bonus: Free Body Diagrams Worksheet (with answer key)

A separate illustrated worksheet designed around the most common misconceptions kids run into with free body diagrams. 20 problems total:

• 15 qualitative scenarios (a book on a table, a chandelier, a hockey puck sliding, a sailboat speeding up, a squirrel on a branch, sliding across the floor in your socks…)
• 5 "make up a scenario to fit this diagram" problems
• A full illustrated answer key with every force labeled

Great for reinforcing what the book teaches, or as a standalone for any kid learning Newton's laws.

A note on answers

The book itself doesn't have a traditional answer key — the practice problems are resolved within the story. For example, the Trickster Fairy walks you through whether each force pair is a third-law pair and why. The bonus worksheet does have a full separate answer key.

What you'll get

• EPUB of the book (for Kindle, Apple Books, Kobo, and other e-readers)
• PDF of the book (for reading on any computer, tablet, or phone — or for printing)
• PDF worksheet with answer key
• Delivered by email immediately after purchase, plus available on your download page

About the author

Sarah Allen tutored math and physics for twenty years before becoming a full-time fantasy writer. She has a physics degree from the University of Washington (graduated with college and departmental honors) and a master's in Cognition and Learning from Columbia. Her goal is to write the sort of physics books she would have wanted as a kid.

Ages 9–12 · 123 pages · Illustrated in color