Atoms are far too small to see unless
you use a very high powered microscope. They are
so small that to make a line
of atoms, three feet 0.9 m long we
would need as many atoms as there are
people on Earth. A single atom makes up an element which is the simplest possible substance
on Earth. For instance one kind of make up the element hydrogen another kind makes up
the element oxygen two or more atoms make
up a molecules make up all the matter on Earth.