PITTSBURGH (KDKA) — When I was younger, my twin brother made a book cover for his physics book. On that cover, he wrote “Book Of Magic” on it.
Mike was sort of right. Physics and magic can go hand in hand.
At least with some creative theatrics, you can make people believe physics is magic.
In the video, I put a metal ball on the top of a jar of unpopped popcorn, and made up a magic word.
After I said the word, and shook the jar, a ping pong ball appeared where the metal ball once was.
So, was it magic? No. It was physics.
Let’s talk about the things we know about this set up.
In the jar, the metal ball is the densest object.
This means it has the most mass per a unit volume of a material.
The ping pong ball has the lowest density, and the popcorn is in between.
While it might not make sense this way, if we switched out the popcorn with water, this scenario makes perfect sense.
When we were to swap the popcorn with water, it makes sense that the ping pong ball will float, and the metal ball will sink, and the water is in between.
We will use the same processes in our scientific “magic trick.”
We just need to give the unpopped popcorn a little help.
So, let’s set this up. Put a layer of popcorn on the bottom of the jar.
Set the ping pong ball in the jar. Pour popcorn on top of it, to hide it.
Now, set the metal ball on top.
When the contents of the container are at rest, nothing is happening.
The ping pong ball is at the bottom, the popcorn is still covering it, and the metal ball is like the cherry on top.
This is where the help comes into play. You need to shake the jar!
When you shake the jar, in any way, the popcorn starts moving.
This creates a movement in the popcorn that mimics water.
A fluid motion that is easily noticed when you shake the popcorn and water next to each other.
That is the motion that allows the physics of density to play out in our experiment.
The object with the most density, the metal ball, sinks in the course, popcorn fluid, and the ping pong ball rises since it has the lowest density.
Just like magic!