Did Isaac Newton get conked on the head by an apple?
Well, that’s not the way he told the story!
I was taught in elementary school that Isaac Newton had solved the riddle of gravity, of how and why stuff falls down.
And yes, Newton really did get inspired by watching an apple fall to the ground. By the time ol’ Isaac was done noodling out how and why it fell, he had created a brand new theory of gravity.
Newton’s theory of gravity was good enough for everything in our everyday lives. It was even good enough to calculate how to send the Apollo spaceships to the moon.
His formula for how gravity works nailed it! Well almost exactly, but that’s a story for another time, and a guy named Einstein. If you are curious about any of this, just read the book!
Newton’s theory of gravity was the first to accurately predict how an apple falls, how a cannonball curves in its flight, how planets orbit our Sun, and how moons orbit those planets.
Here are a few excerpts from my chapter on Isaac Newton:
Newton’s observation of the falling apple was more of a “that’s funny” moment and not so much a “eureka!” moment. Newton acknowledged his reliance on the works of those who went before him by declaring “If I have seen further it is by standing on the shoulders of Giants.” Galileo was one of those “giants,” and one of the critical ideas that Galileo developed in regard to how objects move was the concept of inertia.
Returning again to Newton’s apple, the first Law of Motion says that just because the stem separates from the branch is no reason for the apple to fall — unless some external force is acting upon it. Inertia would keep the stationary apple stationary, suspended in mid-air… unless some external and unbalanced force acted upon it.
Newton expressed his theory of gravity as Every mass attracts every other mass with a force that is directly proportional to multiplying their masses together, and inversely proportional to the square of the distance between them.
“Inversely proportional to the square of the distance between them” in Newton’s law of gravity is just nerd-speak to say that the attraction between two massive objects drops off quickly with distance.
Even a huge attraction between massive objects (when they are close together) becomes very weak at astronomical distances.
If the above scraps from my little book leave you scratching your head, I don’t blame you. You kind of have to read the book to get the full story. Or you can get a quick-and-dirty version from my video for the activity at the end of my chapter on Newton. I cover Newton’s three laws of motion and his law of gravity. And I do the somewhat goofy activity!
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