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Science, Evolution, and Creationism, by the National Academies, focuses on teaching evolution in today's classrooms. Check out the other publications in our online store.
Shown here are four representations chemists use for a molecule of ammonia. In the colored models, nitrogen atoms are blue and hydrogen atoms are white.
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Windows to the Universe original artwork by Randy Russell.

Molecules

Most things around us are 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.

Last modified September 17, 2010 by Randy Russell.

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The Fall 2010 issue of The Earth Scientist, focuses on rocks and minerals, including articles on minerals and mining, the use of minerals in society, and rare earth minerals, and includes 3 posters!

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA