Why are molecules nature's "building blocks"? Because everything around us pizza, skateboards, even your best friend is made of them!

If everything is made of molecules, what are molecules made of? Atoms! Learn all about the structure of atoms at Chem4Kids. Next, find out why atoms bond with other atoms to form molecules. Then check out the Periodic Table of Elements to learn about all the different kinds of elements on earth!

Let's take a look at some real molecules. Find out what water and ice molecules look like and how they behave at the Water and Ice Module at New York University's Math Mol site. Try your hand at the online activity and offline experiment. Next, take a look at carbon and see how this element forms in different ways to create graphite and diamonds. A great background resource is the Mathmol Hypermedia Textbook, which highlights concepts like mass and weight, provides models of atoms and molecules, even shows structures of molecules like sugar and DNA. (There's also a Hypermedia Textbook for kids in grades 35, which includes terrific overview of atoms and molecules.)

Now that you know what molecules look like, let's find out why they're considered nature's building blocks. Check out DNA: The Instruction Manual for All Life, and learn about this molecular structure that tells our bodies how to grow. You'll encounter a close-up of a human hand, then zoom in step by step until you reach the skin cells, then the nucleus where the DNA resides. Continue into the nucleus and take a look at the chromosomes. Go even closer until you can see what DNA molecules look like. Want to go closer yet? Pull apart the DNA helix and look inside. Notice how the bases in the helix make up a sequence. Play the sequence game to see how good you are at finding sequences. How long would a chain of all the DNA in all of the cells of your body be?