Fundamental Forces

The basic forces in nature Click on image for full size (32K GIF) Image courtesy of Contemporary Physics Education Project

There are four forces in the Universe: strong, weak, electromagnetic and gravity. You may be most familiar with gravity. Gravity is what holds you and your dog to the surface of this planet!

The other forces may be less familiar to you, but they are very important! For example, the electromagnetic force holds electrons in orbit around the nucleus of an atom. We need these atom parts to be held together because we're made of atoms!

Table courtesy of University of Guelph, Guelph, Ontario (Cananda)

The basic forces in nature Click on image for full size (32K GIF) Image courtesy of Contemporary Physics Education Project

The interactions in the Universe are governed by four forces (strong, weak, electromagnetic and gravitational).

Physicists are trying to find one theory that would describe all the forces in nature as a single law. So far they have succeeded in producing a single theory that describes the weak and electromagnetic forces (called electroweak force). The strong and gravitational forces are not yet described by this theory.

Table courtesy of University of Guelph, Guelph, Ontario (Cananda)

The basic forces in nature Click on image for full size (32K GIF) Image courtesy of Contemporary Physics Education Project

The interactions in the Universe are governed by four forces (strong, weak, electromagnetic and gravitational).

Physicists are trying to derive a unified theory that would describe all the forces in nature as a single fundamental law. So far they have succeeded in producing a unified description of the weak and electromagnetic forces, but a deeper understanding of the strong and gravitational forces has not yet been achieved.

Quantum physics describes the mutual effect of forces on particles by the "exchange" of other particles. For example, electrically charged particles attract or repel each other by emitting and absorbing photons, which carry the electromagnetic interaction.

Table courtesy of University of Guelph, Guelph, Ontario (Cananda)