Check out how high these different balls
bounce-- the basketball, the super bouncy ball, and the golf
ball.
Now, I'm going to try the golf ball on top
of the bouncy ball on top of the basketball,
and then I'm going to explain how
it's related to a supernova.
Did you see that?
Probably not, so here it is again.
The golf ball bounced to 28 feet.
We dropped it from about 3 and 1/2 feet, so it went up 800%
of its dropped height.
In fact, if you consider that by itself-- the golf ball bounces
about 70% of it's dropped height--
it went as high as if it had fallen from 40 feet up.
That is awesome.
So how can we get the golf ball to bounce up
with that much energy?
Let's simplify it to these two balls.
When you drop them individually, each ball
starts out with some potential energy
from the height of the drop.
As the balls hit the ground, some energy
goes into heating up the ground, and some
goes into heating the ball.
Because that energy left the ball system,
you can't get back up to the same height.
But when you combine them, the tennis ball
goes higher than its dropped height, way higher.
Where does it get the extra energy?
As the basketball bounces, it compresses, storing
elastic potential energy.
As it releases, it springboards the tennis ball upward
just at the right moment.
This is like the double bounce on a trampoline
when you jump right before someone else.
You prepare the elastic of the trampoline
by stretching it and storing energy, which can then
bounce the jumper even higher.
In the same way, the basketball stores energy
in its compression and is able to push the tennis ball,
but just like the double bounce preparer,
the basketball can't go as high.
You can see that here.
It bounces even less when three balls are dropped together.
Also during that transfer of energy,
some momentum transfers from the basketball to the tennis ball,
and since the basketball starts with way
more momentum because of its larger mass, the tennis ball's
velocity increases by a lot.
And it flies up, up, and away.
Now, back to the triple super ball bounce.
Now, do you get the energy from the basketball's bounce being
transferred into the bounce of the super bouncy
ball, which is then transferred to the golf ball's bounce.
You put the same amount of energy or momentum
from two more massive objects into a smaller object,
and it will go much faster, epic,
just like the explosions of a supernova, which
may seem unrelated.
But what we just did is analogous to the process
that occurs during the explosion of a supernova.
Just like our more massive basketball transfers momentum
to the smaller balls, energy from the dense core
of the supernova is transferred in a shockwave that
moves through the star to the less dense layers
and accelerates them outward at a super high velocity.
More massive or denser layers in the core of the supernova
begin to collapse when fusion stops there.
The collapse is halted when the neutrons in the core
actually touch, sort of.
This causes the implosion to rebound and bounce outward.
You end up with a dense core left behind
and these wild outer shells of star exploding outward, pretty
cool.
And, of course, if you try this at home, which you should,
you have to make sure the balls are perfectly vertically
aligned because any off centeredness gets amplified
by the two points of contact, which
is why we sadly couldn't get the quadruple tower of balls
to work.
But if you put a little ring of hot glue or something
similar on the balls, it helps to balance them.
Happy physicsing.
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