While there are only a finite number of elements on Earth (118, give or take), there is a seemingly endless number of different substances to be found. If our fairly limited array of elements are the building blocks for every substance on the planet, isn’t there a limit to the ways they can be arranged? Shouldn’t that limit, therefore, restrict the quantity of different substances that can possibly be created? In other words, how do we get billions and billions (probably—maybe even more) of different things—from rocks to trees to goats and cheese—from only 118 different pieces?
For a quick and easy demonstration of how this seeming impossibility shakes out, all you’ll need are two student volunteers and sixteen identical Lego pieces. I prefer blue 6-by-1-by1s, but that’s just me. As long as all your pieces are the same color and shape/size, you’re good to go.
Give half your Lego bricks to student A and the other half to student B. Send student A to one side of the room and student B to the opposite side. Have them sit so they’re facing away from each other—no peeking! Then, ask them to build whatever they want with their pieces. It shouldn’t take very long, as they’ve only eight pieces to work with each.
When they’re finished, show their creations to the class. Barring an incredible coincidence or mental telepathy between your students, you’ll end up with two completely different structures.
What Does This Mean?
It’s all about structure. Here, your students have constructed two unique creations using identical components. Similarly, diamonds and graphite (for example) are both comprised solely of carbon atoms, but exhibit totally different characteristics.
The reason for these differences is the way those elemental atoms are structured. The atoms in a diamond, all carbon, are arranged in one specific way—like student A’s Lego construction, built from all one kind of brick. The atoms in graphite, also all carbon, are arranged in a totally different way—just like student B’s Lego construction.
By fiddling with atomic arrangements, it’s possible to create infinite substances using our 118 available elements.