:: molecules ::

Most molecules are far too small to see with our two eyes. Molecules are made up by two or
more atom that combines together by chemical bond. Molecules may contain two atoms of the same element. For example O2 or H2. Two atom hydrogen combine an form H2. Or maybe contain a same element. For example like water. Two atoms of hydrogen are combine with 1 atoms of oxygen and become a molecules of water which is H2O.