When it comes to demonstrating the beauty of physics, few people manage to simplify complex concepts as effectively as Physics Girl.
In one of her videos, she takes a seemingly innocent and playful science experiment—stacking a golf ball on top of a bouncy ball, on top of a basketball—and uses it to explain a phenomenon as colossal as a supernova.
It’s a jaw-dropping demonstration that starts with a simple question: What happens when you drop a stack of balls?
You might be surprised by the answer, and the intriguing physics behind it may leave you questioning everything you know about energy, momentum, and even the workings of the universe.
A Surprising Jump in Height: The Power of Energy Transfer
Let’s break down the experiment first. Imagine this: you have three balls—a golf ball, a bouncy ball, and a basketball—stacked one on top of the other.
You lift the stack and drop it.
When the golf ball is dropped by itself, it reaches a height of about 106 cm.
Now, here’s where it gets really interesting.
When the same golf ball is placed on top of the bouncy ball and the basketball, the bounce skyrockets to over 8.5 meters—800% higher than its original bounce!
So, what’s happening here?
How is the golf ball achieving such a dramatic leap? The answer lies in energy transfer and momentum.
Each ball has a certain amount of potential energy because of the height from which it’s dropped.
As the balls hit the ground, a portion of that energy is dissipated as heat—both in the ball and in the ground.
Typically, this means the ball will never bounce to the same height from which it was released.
However, when you stack the balls, something extraordinary happens.
The bouncy ball and basketball store and release energy in such a way that it propels the golf ball to unprecedented heights.
Physics Girl explains it well: “As the basketball bounces, it compresses, storing elastic potential energy.
As it releases, it springboards the golf ball upwards, just at the right moment.”
The basketball doesn’t bounce as high as it would on its own, because much of its energy is transferred to the smaller golf ball on top.
This transfer of momentum—from a larger mass to a smaller one—is the key to the golf ball’s stunning performance.
The larger mass (the basketball) has more momentum to give, which helps propel the smaller object (the golf ball) much higher than it could on its own.
The bigger ball transfers its energy to the smaller one, creating a more dramatic and energetic result than you might have expected.
What Does This Have to Do With Supernovae?
Now, here’s where the mind-blowing connection comes in.
At first glance, this experiment might seem like child’s play—simple, straightforward, and even a bit silly.
But Physics Girl has a habit of tying such experiments to some of the most massive and complex phenomena in the universe.
So, how does the stacked ball drop connect to a supernova?
To understand this, we need to dive into the idea of energy transfer and momentum once again, but this time on a cosmic scale.
Just like the stacked balls, a supernova involves the release of enormous amounts of energy. In fact, a supernova is one of the most violent and powerful events in the universe, marking the death of a star.
During a supernova, a star’s core collapses under its own gravity, causing an incredibly energetic explosion.
The energy released in this explosion is staggering—it’s the equivalent of our entire Sun’s energy output over millions of years.
In a supernova, the massive star (like the basketball) is collapsing inward, and in doing so, it releases its energy outward, much like the energy transfer in the ball drop experiment.
While the mechanics of the two events are vastly different in scale, they share an essential principle: the release and transfer of energy from a larger mass to a smaller one.
In both cases, something bigger (whether a ball or a star) releases its energy in a way that propels a smaller object (the golf ball or the elements expelled during a supernova) to new heights, figuratively and literally.
It’s a stunning example of how the laws of physics—momentum, energy transfer, and compression—apply across the spectrum, from high school science experiments to the most extreme phenomena in the universe.
Energy Transfer in a Supernova: Not Just a Bouncing Ball
Let’s get deeper into the comparison. In a supernova, the energy released by the star isn’t just a one-time explosion.
The intense pressure and heat generated in the explosion cause the star’s outer layers to expand rapidly, and these layers collide with the surrounding interstellar medium.
This high-energy collision spreads the star’s materials—heavy elements like iron, nickel, and other metals—out into space, enriching the interstellar medium with the building blocks for new stars, planets, and even life.
The key here is that the larger star (like the basketball in the experiment) transfers its energy to the smaller objects in the explosion, pushing them to incredibly high speeds.
These materials get scattered across vast distances, playing a crucial role in the formation of new stars and planetary systems.
The concept is similar to the momentum transfer seen in the ball drop experiment: large masses push smaller objects to surprising heights.
In fact, the materials scattered by a supernova eventually contribute to the formation of planets, stars, and even the very elements that make up our bodies.
So in a sense, the energy released during a supernova has lasting effects on the formation of the universe itself—just like how the energy transferred from the basketball to the golf ball in the drop experiment leads to an impressive and unexpected result.
The Grand Connection: From Ball Drops to the Cosmos
What’s really remarkable about this comparison is the universal applicability of the laws of physics.
Whether it’s a bouncy ball, a collapsing star, or an exploding supernova, the same fundamental principles govern all these systems.
In both cases, energy and momentum are transferred from a larger mass to a smaller one, creating unexpected and sometimes overwhelming results.
As Physics Girl beautifully illustrates, this is the magic of physics: it applies universally, from the mundane to the mind-boggling.
The same forces that govern the simplest science experiments in a classroom also shape the birth and death of stars in far-off galaxies.
And while a supernova might seem worlds apart from a playful ball-drop experiment, at their core, they share the same physical principles that make the universe function the way it does.
Final Thoughts: Physics Is Everywhere
What can we take away from all of this? One of the most profound insights is that physics is not just a subject confined to classrooms or laboratories—it’s the very force that drives the universe.
The same rules that govern the behavior of a simple ball in freefall are responsible for the dramatic explosions and formations that occur on a cosmic scale.
So the next time you see a golf ball bounce unexpectedly high on a stack of other balls, remember that the forces at work are the same ones that have shaped the stars and galaxies for billions of years.
Whether it’s a supernova or a schoolyard experiment, physics has an undeniable beauty that transcends both scale and time.
