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The basic forces in nature
Contemporary Physics Education Project

Fundamental Forces

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!


Interaction Relative Strength Range Mediating Particle
Strong 1 Short Gluon
Electromagnetic 0.0073 Long Photon
Weak 10-9 Very Short W,Z
Gravitational 10-38 Long Graviton

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

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part by the National Science Foundation and NASA, our Founding Partners (the American Geophysical Union and American Geosciences Institute) as well as through Institutional, Contributing, and Affiliate Partners, individual memberships and generous donors. Thank you for your support! NASA AGU AGI NSF