There are four such forces:
Gravitational Force
This is the binding force of
the solar system and
galaxies. It acts between all
particles and pulls
matter together.
Electromagnetic Force
This is the binding force of
atoms, demonstrated when
unlike charges attract. A cloud of negatively charged
electrons will stay near a positively charged
nucleus.
Strong Force
This is currently believed to be a remnant of a more powerful "colour force" acting on
quarks inside the
protons and neutrons. A nucleus, composed of positive charged protons, will not blow apart, since
like charges repel, due to this force.
Weak Force
A neutron breaks up, emits an electron and becomes... a proton! This causes
radioactive decay of some nuclei. When operating in this fashion, this force is 1,000 times weaker than a
strong force. The higher the frequency of energy, the stronger and more electromagneticish (new word) this force becomes.
With these four forces combined, we form... um... something pretty damn cool.