Although there are apparently many types of forces in the Universe, they are all based on four fundamental forces. The strong and weak forces only act at very short distances and are responsible for holding certain [[nucleons]] and compound nuclei together. The electromagnetic force acts between [[electric charge]]s and the gravitational force acts between [[mass]]es. The [[Pauli exclusion principle]] is responsible for the tendency of [[atom]]s not to overlap each other, and is thus responsible for the "stiffness" or "rigidity" of matter, but this also depends on the electromagnetic force which binds the constituents of every [[atom]]. | Although there are apparently many types of forces in the Universe, they are all based on four fundamental forces. The strong and weak forces only act at very short distances and are responsible for holding certain [[nucleons]] and compound nuclei together. The electromagnetic force acts between [[electric charge]]s and the gravitational force acts between [[mass]]es. The [[Pauli exclusion principle]] is responsible for the tendency of [[atom]]s not to overlap each other, and is thus responsible for the "stiffness" or "rigidity" of matter, but this also depends on the electromagnetic force which binds the constituents of every [[atom]]. |