Yes, a grain of sand can enlighten you about some deep secrets of our universe ... if you look at it deeply enough, and leave all your scientific, religious and philosophical biases aside.
Hold the grain of sand on the tip of your index finger and think "Why does this grain of sand exist?" Where did it come from? Where did everything come from? Why do things exist? Was there a moment of creation which created everything we see? Have things existed forever without any creative force?
Ponder on these lines and it will lead you to one of the models about the creation$^1$ of universe or how things came to be.
Carefully drop that grain of sand from your fingertip on the palm of your other hand and notice how it falls down! Isn't that amazing? Why does it fall? What is falling? What makes the grain of sand fall? Move to a different location and repeat the experiment. Does it always fall down? What is down? Why does the grain of sand always fall towards Earth? Is Earth pulling on that grain of sand? Jump upwards and see if you can go into space like that. Can you? Does Earth pull on you too? Does Earth pull on everything? Why does Earth pull on everything? Why is it easier to lift lighter things than heavier things? What makes things light and heavy?
Think and if you think deep enough and clearly enough, you will start to form an idea about mass and matter and how gravity works.
Carefully rotate the grain of sand in sunlight and notice how it starts to shine at one point/angle. What makes it shine? Why doesn't it always shine at all angles? Does it have something to do with the alignment of the sun, the grain and your eyes? Does the grain of sand shine by itself or does it reflect the light of sun?
Place the sand grain at different angles and notice at which angle it shines. Think about the alignment of the sun, the sand grain and your eyes. Does it tell you something about the laws of reflection? If you want to think deeper, think about the nature of light. What is light? Where does it originate from? How does it enable us to see?
What is sand?
So then. Why do we call it sand? What is the difference between yourself and the sand gain? How is it different from air? Can we take the grain of sand apart and see what it is made of? How do we take it apart? If we heat it enough, can we split it into its parts?
Try heating the sand grain and notice how it changes color. Heat it more and you will see it melts! If you heat it enough, you will see it reduces to a grayish colored substance. What does this mean? If you keep heating this grayish substance, it only melts and then vaporizes, but does not reduce to anything else. What does it mean? Is that grayish substance the core part of sand? What is the other part that must combine with it to form the sand grain?
Think on these lines and you will start to form an idea about basic chemistry, thermal decomposition and additive reactions.
Si + O$_2$ =======> SiO$_2$
I could go on and on with with this, but i think the point has been made.
- By creation I mean the moment when everything came into existence. No bias intended towards creationism. Creation of the universe from God or without God is a completely different (and unrelated) discussion.