What’s a molecule?

A cartoon drawing of water molecules. Each round ball represents an atom. The smaller round balls are hydrogen atoms and the larger balls are oxygen atoms. Click on image for full size (171K GIF) Courtesy of Corel

Everything around us is made of groups of atoms bonded together into packages called molecules. The atoms in a molecule are held together because they share or exchange electrons.

Molecules are made from atoms of one or more elements. Some molecules are made of only one type of atom. For instance, two oxygen atoms bond together to form the molecule O2, the part of the air that we need to breath to survive. Other molecules are very large and complex. Protein molecules, for example, often contain hundreds of atoms.

Other well known molecules include water, which is two hydrogen atoms bonded to one oxygen atom (H2O), and carbon dioxide, which is one carbon atom bonded to two oxygen atoms (CO2).

Each molecule is so small that you would not be able to see one molecule of a substance. But when thousands of molecules are together, they might look like a glass of water, a tree in the forest, or your computer screen, depending on what types of molecules they are.

A glass of water sitting on a table might look pretty still, but the molecules of water (H2O) and glass (Si) are moving all the time. In fact, though too small to see, all molecules are always moving and they will move faster as temperature increases.

A cartoon drawing of water molecules (H2O). Each round ball represents an atom. The smaller round balls are hydrogen atoms and the larger balls are oxygen atoms. Click on image for full size (171K GIF) Courtesy of Corel

Everything around us is made of groups of atoms bonded together into packages called molecules. The atoms in a molecule are held together because they share or exchange electrons.

Molecules are made from atoms of one or more elements. Some molecules are made of only one type of atom. For instance, two oxygen atoms bond together to form O2, the part of the air that we need to breath to survive. Other molecules are very large. Protein molecules, for example, often contain hundreds of atoms.

Even large molecules are so small that you would not be able to see one molecule of a substance. But when thousands of molecules are together, they might look like a glass of water, a tree in the forest, or your computer screen, depending on what types of molecules they are.

Even if a soccer ball is sitting still, the molecules within it are moving all the time. They may be too small to see, but molecules are always moving and they will move faster as temperature increases.

A cartoon drawing of water molecules. Each round ball represents an atom. The smaller round balls are hydrogen atoms and the larger balls are oxygen atoms. Click on image for full size (171K GIF) Courtesy of Corel

Everything around us is made of groups of atoms connected together into packages called molecules.

Molecules are made from atoms of one or more elements. Some molecules are made of only one type of atom. Other molecules are very large and are made of hundreds of atoms.

Even large molecules are so small that you would not be able to see only one molecule of something. But when thousands of molecules are together, they might look like a glass of water, a tree or even your computer screen!