The smallest things of all

To understand the world around us
And know the cosmos with less doubt
To comprehend that there is something
Instead of nothingness throughout

If we're to make sense of it all
Ask the "why" that matters most
We should turn our focus inward
To the smallest things that we can know

For centuries great thinkers pondered
How this world could be comprised
Is there an underlying constant
To the world before our eyes

Ancient greeks proposed a particle
So infinitely small
And they called these constructs atoms
The smallest things of all

From the structure of the atom
All the elements are known
And from elements come molecules
As chemistry has shown

First a nucleus sits densely
In the center of a sphere
And its core is protons bound to neutrons
The atom's mass is mainly here

About the nucleus buzz particles
That are vastly smaller still
Electrons with their minus charge
In their orbitals they spin at large