Gravity: A Fairy Tale

A full-length middle grade novel that teaches gravity, orbits and tides inside the story — 206 pages, eighteen chapters, for readers ages 9–12. Paperback, with color illustrations by Marie Delwart.

Read a Sample

What would happen if you jumped into a tunnel that ran straight through the center of a planet?

Worry is about to find out. Her sister Hope has been taken by a dragon, and Worry means to bring her home — a journey that will take her from the center of her own planet to the surface of a nearby moon, with a ghost-cat named Kepler for company and the echoes of Aristotle, Galileo, Newton and Einstein turning up along the way, arguing with each other about how gravity works and being wrong in instructive ways.

If you own Fairy Tale Physics: Books 1–4. Gravity is Book 4 of that collection, and the two are the same book — not a revised edition, not an expansion. If you have the omnibus, you already have this story. This page is for readers who want it on its own.

What's inside

Eighteen chapters, with the science carried inside them rather than collected at the back. Where the story runs into something worth understanding, the book stops and explains it, and often asks you to go and try it:

• Hands-on activities using what's already in the house — drawing a true ellipse with string, thumbtacks and cardboard; using magnets to hunt for something invisible; timing a pendulum with a stopwatch and a necklace to work out what actually changes its swing; taking your own tide data to see why the tides took so long to explain
• Discussion questions and a writing prompt — including one at the start that asks what you already believe about gravity, before the book tells you anything
• Free online simulations, linked where they help: the PhET Pendulum Lab and Gravitational Force simulators, GravitySimulator.org for rearranging the solar system, the Exploratorium's Falling Rhythm, and a scale model of the solar system that takes a very long time to scroll through

The physics it covers

• Newton's Law of Universal Gravitation
• Circles and ellipses
• How orbits work
• Tides and planetary motion
• Pendulums
• Logical reasoning and syllogisms
• A short history of gravity, from Aristotle to Einstein

What this book doesn't have: problem sets and answer keys. Newton's Laws and Fluid Mechanics end with quantitative practice problems worked all the way through; Gravity doesn't. The explanations, activities and questions sit inside the chapters instead, and the math stays optional. If you came here for algebra practice, those are the books that have it.

After the ending, the book closes with an excerpt from Physics Fables — the opening of "Sakura and the Many-Layered Sea," a story about density and buoyancy.

Digital downloads included with your order

• A PDF of the book — for any device, or for printing
• An EPUB — for Kindle, Apple Books or Kobo
• "Abigail's Totally Purposeful, Definitely Not Accidental or Dangerous, Adventure" — a PDF bonus story — 7,000 words with the same characters, in which a birthday present for Galileo turns into working out exactly what makes a pendulum keep time

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.

Shipping: this is a print-on-demand paperback — please allow 2–3 weeks for printing and delivery. If you need your copy sooner, it's also available on Amazon with faster shipping.

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 · Middle grade novel · 206-page paperback · Color illustrations · Book 4 of Fairy Tale Physics · Includes book PDF, EPUB and bonus story PDF