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Classic Episode Guide > Physical Science > Atoms and Molecules

Atoms are reeeeally small. They are so small that you can’t see them with just your eye. It takes as many as 10 million of them side-by-side to measure a single millimeter. In fact, atoms are the smallest pieces of “stuff” that are still considered “stuff.”

If you take something and break it into tiny pieces, and then break it into tinier pieces, and keep going, the smallest part you’d be left with (and still have the same substance that you started with) is an atom. Atoms are the building blocks of all matter. Everything is made of only 109 different kinds of atoms, called elements. 92 of these elements occur naturally, but the rest of them – ones like Technetium and Promethium have only been found in distant stars and Californium and Einsteinium – are only made in laboratories. A molecule is born any time two or more atoms combine together.

All of these kinds of atoms make up everything in the Universe by combining with each other to create molecules of new kinds of stuff.

The Big Ideas

  • Matter is made of tiny pieces called atoms.
  • Atoms are smaller than you can see with your eyes, or even a microscope.
  • Matter is made of combinations of 92 different atoms.

Did You Know That?

  • Most of an atom is empty space? More than 99.9 percent of the mass of an atom is located in its dense central nucleus.
  • Even though there are only 92 natural elements, they combine to a total of more than 5 million different known molecules?

Books of Science!

  • “The World of Atoms and Quarks”by Albert StwertkaTwenty-First Century Books, 1995.
  • “Janice VanCleave’s Molecules”by Janice VanCleaveJohn Wiley Sons, 1993.
Bill Nye