Photo by: Getty Images

Getty Images

Feathers and Bowling Balls Act Strangely in a Vacuum

You can recreate your own version of this famous experiment.

August 01, 2019

Sometime in the third century B.C., Aristotle wrote that heavy objects fall toward Earth faster than lighter ones. His explanation for this behavior was profoundly influential, sophisticated for its time, and almost completely wrong. Almost 2,000 years later, Galileo proved that heavy objects and light objects fall to Earth at exactly the same rate. You can perform his experiment yourself.

No, This Doesn't Defy Gravity

At first glance, it's easy to side with Aristotle. If you drop a feather and a bowling ball from the same distance anywhere on Earth, they will fall at different rates. The feather will drift breezily to the ground while the bowling ball plunks downward immediately. But this explanation leaves an important factor out of the equation: air resistance. Since the feather is so light, air pressure acting on it from all directions is strong enough to counteract the force of gravity, which acts on it uniformly regardless of its weight.

Galileo proved Aristotle wrong with a simple stroke of genius — he used two cannonballs (bowling wasn't popular in 16th century Italy, but cannons were) and dropped them both off of the Leaning Tower of Pisa. If Aristotle was right, then the smaller cannonball should fall at a slower rate than the larger one. Instead, they both fell at the same exact speed: 9.8 m/s². Galileo's experiment became one of the most important pieces of the puzzle that Isaac Newton would later use to establish the modern theory of gravity.

You can recreate your own version of Galileo's experiment by tying a feather to a bowling ball and dropping them both at the same time. The feather-bowling ball duo doesn't fall at a slower rate because the feather is lighter than just the bowling ball alone — instead, they both fall at exactly the same rate. Similarly, if you pump all of the air out of a glass chamber to create a vacuum, you can drop both the feather and the bowling ball — no strings attached — and watch them hit the ground at the exact same time.

No Vacuum Chamber, No Problem

This experiment doesn't necessarily require a cumbersome vacuum chamber. Apollo 15 astronaut David Scott famously recreated this experiment on the moon in 1971 using a falcon feather and a hammer. Scott, an MIT-educated aeronautics engineer, knew his physics, so the fact that the feather and hammer hit the surface of the moon at the same time was no surprise. The moon has an atmosphere 10 quadrillion times less dense than the Earth's — so weak, in fact, that statically charged moon dust levitates around 10 centimeters above the surface of the planet. Despite the fact that modern audiences know what the outcome of Scott's experiment is, the live broadcast remains a sight to behold and a historical treasure.

This article first appeared on Curiosity.com.

Next Up

Check Out the Crab Nebula –The Leftovers from a Giant Cosmic Firework

The Crab Nebula sits 6,500 light-years away, and is currently about 11 light-years across. But while it looks pretty from afar, don’t give in to the temptation to visit it up close.

Farewell, Earth’s Mini-moon

It's time to say goodbye to the mini-moon that's no bigger than your car.

Celebrating Hubble's 30 Year Legacy

Three cheers for the Hubble! First launched in 1990 aboard the Space Shuttle Discovery, the storied space telescope is celebrating is thirtieth year in lonely orbit around the Earth.

Check out the Earth’s 800,000 Year Old Battle Wound

Scientists may have discovered the location of an ancient buried crater, a result of a meteorite that barreled into the Earth some 800,000 years ago.

Get Celestial with Lowell Observatory LIVE!

Our friends at Lowell Observatory are serving up our solar system on a platter live!

Scientists Have Discovered Enormous Balloon-Like Structures in the Center of Our Galaxy

There's something really, really big in the middle of our Milky Way galaxy — one of the largest structures ever observed in the region, in fact.

DNA's Building Blocks May Have Their Origins in Outer Space

One of life's building blocks could have originated in outer space. But if this experiment shows how these building blocks actually formed, how exactly did they get to Earth?

When Was There Life on Venus?

What we have is a cosmic whodunit. Venus, the second planet from the sun and considered by the more romantic types as "Earth's twin" and the avatar of love, is dead.

Where should we go? The Moon or Mars?

There’s been a lot of excitement around space exploration recently. Astrophysicist Paul M. Sutter discusses the viability between the Moon and Mars.

Welcome to the Surface of Mars

Through the use of cutting-edge instruments, scientists finally have the opportunity to probe deep beneath the surface and ascertain exactly how the terrestrial planet formed.