The Misconception of Gravity - Part 1

Drop an iron ball and a strand of feather from a height, which one will fall to the ground first?

Seems like a simple question and 99% of children or adults will say the iron ball will fall much faster as it's heavier than the feather. Well, they are all right as indeed that is what will happen if we do this in our normal environment with air. But we need to remove the impact of air to truly understand the impact of gravity alone.

Now let's say we do the same experiment but suck out all the air of a closed chamber and do the same experience inside that vacuum chamber. Now what do you think will happen?

It is hard to believe as it betrays our intuition.

Further, this was confirmed on the moon where a hammer and a strand of feather fell to the ground at the same time. Remember although gravity is less on the moon than on Earth, there is no air on the moon, so it's like a vacuum chamber.

So now if you are scratching your head. Here is the much-awaited explanation of what is happening :

On earth, we are living in an air-filled world that is opposing the "fall" due to friction. The iron ball due to its smooth surface experiences far less friction than the strand of feather. So the iron ball falls much faster. But if we remove air, friction is eliminated and we see the true nature of what is happening as the object is falling. The object is not "falling"! Hold that thought.

Mathematical Explanation

Let's look at two equations we know from Newton's world of gravity.

1.Newton's second law states a force will move an object with mass with an acceleration

force = mass of the object X acceleration

2.Newton also calculates the force of gravity through the below equation

force on the feather = ( mass of feather X mass of earth ) / Radius of earth X Radius of earth

force on the iron ball = ( mass of iron ball X mass of earth ) / Radius of earth X Radius of earth

So equating the two force equations 1 and 2...

mass of feather X acceleration of the feather = ( mass of feather X mass of earth ) / Radius of earth X Radius of earth

mass of iron ball X acceleration of the iron ball = ( mass of iron ball X mass of earth ) / Radius of earth X Radius of earth

OR

acceleration of the feather = mass of earth / Radius of earth X Radius of earth

acceleration of the iron ball = mass of earth / Radius of earth X Radius of earth

OR

acceleration of the feather = acceleration of the iron ball!

So the acceleration only depends on the mass of the earth and its radius. In other words, it does not depend on the mass of the object falling!

Intuitive Explanation

What is happening here is the force on the iron ball is much more than the force on the feather as the force depends on their mass. So the earth is pulling the heavier object i.e. the iron ball more than the feather but the net effect is that the acceleration for both is the same.

Imagine you are pulling a heavy box versus and lighter box on the floor. You will exert more force on the heavier box compared to the lighter box to move both boxes at the same speed.

In reality, the feather and the iron ball are not falling, but instead, they are moving towards the earth due to a curvature created by the earth.

Try it yourself

You don't need to go on the moon or create a vacuum chamber to see this happening.

1. Take 1 A4 sheet of paper and crumple it into a ball.

2. Take 2 A4 sheets of paper and crumple both into a ball together to make 1 ball.

3. Ensure the 2 paper balls are similar round shape and size ( so friction applies equally to both eliminating the role of friction)

4. Drop both of them from a height and see what happens.

They have different masses ( just like the iron ball and the feather ) but they still reach the ground at the same time!

This is just one of many things that betray our intuition as we don't perceive how the universe works. In short, we need to elevate our perspective to truly understand where we live and the rules that govern our physical world. Don't worry if this still sounds weird. It does need a different perspective to clearly understand our physical universe and yes they don't teach this in school. Lots more coming up on this in future posts.

Are you ready to bend your mind? Here are more interesting reads on similar experiments done in history

Want to rekindle your curiosity and/or have curious kids? Be the next Albert Einstein with these cool 101 science experiments. Discover how to bend light, construct a circuit, see sound, build a buzzer, make a rainbow, and even make an underwater volcano.

If you want more of Gravity and love fiction, then you may enjoy my graphic novel from the series "Ventures in Space and Time" : Kohiti's Anomaly