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

Why Does Pluto Have Such a Weird Orbit?

Pluto is the black sheep of the planets in our solar system and it looks like astronomers aren’t sure how long Pluto will remain in its present orbit.

Why We'll (Probably) Never Be Able to Teleport

For many of us, teleportation would be the absolute best way to travel. Imagine just stepping into a transporter and being able to go thousands of miles in nearly an instant.

That’s a (Weirdly) Big Black Hole!

Recently astronomers identified a black hole near a star called LB-1 and they found out that the black hole is 70 times the mass of the sun. This is a mystery because the biggest black holes we can get from the deaths of the most massive stars are around 30 times the mass of the sun, so how did black hole get this big?

Following Blue Origin’s NS-12 Rocket Launch

Blue Origin, Billionaire Jeff Bezos’ spaceflight company, is rescheduled to launch its NS-12 reusable spacecraft on Wednesday, December 11. Watch it LIVE.

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.

SpaceX vs. the Universe

Fans of space are having a tough time picking sides over a recent controversy between SpaceX and astronomers. But what's the big debate all about? Astrophysicist Paul M. Sutter digs into both perspectives.

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?

The Coronavirus: What You Need to Know About the Virus

As the death tolls rise, Coronavirus is on the minds of people all over the world. Learn about this new virus and how we got here. Originally published: 2/20/2020 Updated: 3/9/2020

2020: A Year of Big Leaps for Mankind

Here are a variety of some amazing space launches to look forward to in 2020.

Last Call for the King of Planets

This month Jupiter is entering conjunction which means it's the last chance this year to catch a glimpse of the largest planet in our solar system.