Chapter 6

Newton Asks “Why?”

“Touch a scientist and you touch a child.” ~ Ray Bradbury

Why an Apple Falls, and Why a Planet Orbits the Sun

What’s the big deal about Isaac Newton?

All of the insights that Newton had about mathematics and about how the physical world works? You could write a book. Well OK, he did. More than a dozen actually.

The scientific revolution had inspired lots of folks to test the real world, and winnow out the good theories from the flawed ideas — using that new-fangled scientific method. But even though Galileo had shown that Aristotle was wrong about gravity a century earlier, Aristotle’s ideas were still being taught when Isaac Newton got to Cambridge. Newton was not amused.

Then, in a horrific stroke of luck, the plague came back. It was the 1665 edition of the bubonic plague in England. Cambridge closed to avoid spreading the disease. Newton went home to the family farm. In his two years of extreme social distancing, he invented calculus, clarified his laws of motion, and (oh yeah) watched an apple fall to the ground while sipping tea.

Newton asked “Why?” Not just how the apple fell down, but why?

“Why” is a much more powerful question than “how.” Newton’s answer is taught in schools and used to this day in engineering because it works so darned well. For the human scale of existence, Newton’s gravity is all you need. And it doesn’t hurt your brain — like general relativity, loop quantum gravity, or string theory do.

You’ll just have to read this chapter to get my plain English take on Newton’s Laws of Motion and his theory of gravity.

The you-can-do-this-at-home activity for Chapter 6 demonstrates a little about Newton’s Laws of Motion, and how they relate to his “mass attracts mass” theory of gravity. Enjoy.

Activity Video for Chapter 6

Here are the links from the text in Chapter 6:

27. Biography “Isaac Newton | Biography, Facts, Discoveries, Laws ….”

28. Deeper Dive “Scientific Revolution – Wikipedia.”

29. Deeper Dive “Newton’s cannonball – Wikipedia.”

30. Deeper Dive “May 25, 1945: Sci-Fi Author Predicts Future by Inventing It ….”

31. Great Video “Galileo’s Measure Of Gravity Explained By Jim Al-Khalili – YouTube.” 9 Nov. 2019, Warning: Starts with ads.

32. Physics-Speak “Newton’s Laws of Motion | Glenn Research Center | NASA.” 25 May. 2021,

33. Physics-Speak “gravity – Newton’s law of gravity | Britannica.”