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

An illustrated fairy tale that teaches Newton's three laws of motion inside the story — 123 pages, full-color illustrations, for readers ages 9–12. Second edition. EPUB and PDF, with a bonus worksheet.

Read a Sample

Kip sets out to seek his fortune with nothing to his name but an apple. Newton is an eccentric wizard who keeps working out how the universe operates by accident. Between them — along with the rival wizard Leibniz, the contested heir Prince Eric, and a guard captain very devoted to him — they discover the three laws of motion, and (mostly) save the kingdom.

Written by Sarah Allen, illustrated in full color by Sheila Stephanie Elizan.

Which edition this is

This is the second edition, and it differs from the first-edition version collected in Fairy Tale Physics: Books 1–4. Same story, more illustrations, and the practice is now woven into stories rather than sitting at the back as problem sets. One difference worth knowing before you choose: the first edition in that collection has quantitative practice problems and answer keys, including algebra, and this edition doesn't. If you want the math, the omnibus is the one that has it. If you want the story to carry the physics, this is the one.

What's inside the book

Four chapters of fairy tale, the first 76 pages — Kip leaves home with an apple, and he and Newton discover the three laws of motion in the wild, by tumbling over cliffs, picking up rocks on the road, arguing with Leibniz, and climbing a tower that won't stop swaying in the wind. One chapter of setup, then one for each law.

Four "A Note from the Librarian" sidebars, which stop where the story does and explain what just happened: entropy, friction, gravity, and the difference between weight and mass. They're optional — skip them and the story still works.

Three "Try to Break the Law!" experiments, one per law, using a rolling chair, a wall, a friend, a sock. The invitation is genuine: try to break it, and find out why you can't.

Five practice sections, pages 77 to 105, with the practice worked into stories rather than set as exercises:

• One — Drawing Forces: a worked free-body-diagram example told as a story, in which Newton has invented a way to keep track of forces and Kip spots what he's missed
• Two — Draw Your Own Free-Body Diagrams: nine to draw yourself — a unicorn standing in a clearing, a troll dragging a sack, a pirate hauling a magical fish up the side of a ship, a dragon flying, the same dragon diving, a fairy failing to shift a golden tiara, a trunk in a speeding wagon, that trunk sliding along the ground, and a cannonball at the top of its arc. Several come with a harder version for anyone who wants it.
• Three — Answers: eleven pages of them, talked through rather than listed, including the two or three that catch nearly everyone out
• Four — The Fairy Tale Historian writing prompt: you've been appointed official bard of the land of fairy tale physics; write your own story about the Second Law
• Five — Riddles in the Woods: the Trickster Fairy sets Kip three questions about whether a pair of forces is really a third-law pair, with ten years and ten days in the woods riding on the answers

A vocabulary list at the end covering force, perpendicular, normal, weight, mass, velocity and acceleration in plain language.

A note on answers. Every diagram problem is answered — Practice Section Three is eleven pages of them — but they're explained rather than listed, talking through what the forces are and why. The Trickster Fairy's riddles are answered the same way, inside the scene. The bonus worksheet has a separate full answer key of its own.

Plus a bonus: the Free Body Diagrams worksheet PDF, with answer key

A separate illustrated worksheet built around the misconceptions kids actually run into with free body diagrams. Twenty problems:

• 15 scenarios to draw — 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 that run the other way — here's a diagram, invent a situation that fits it
• A full illustrated answer key, with every force labeled

It works alongside the book, or on its own for any kid learning Newton's laws.

What you'll get

• An EPUB of the book — for Kindle, Apple Books, Kobo and other e-readers
• A PDF of the book — for any computer, tablet or phone, or for printing
• A PDF of the Free Body Diagrams worksheet, with its answer key

All three are ready the moment you check out — the download buttons are on the confirmation page. Your order confirmation email also has a View Order and Downloads button, which takes you back to your order page to download them any time.

Looking for the paperback? Newton's Laws: A Fairy Tale is also sold as a printed book, which comes with these same files. This page is the digital edition on its own.

About the author

Sarah Allen tutored math and physics for twenty years before becoming a full-time 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 · Second edition · EPUB and PDF, plus worksheet PDF