The basic forces in nature
Contemporary Physics Education Project

# Fundamental Forces

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.

FUNDAMENTAL FORCES

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

## Traveling Nitrogen Classroom Activity Kit

Check out our online store - minerals, fossils, books, activities, jewelry, and household items!...more

## Neutrinos

The neutrino is an extremely light (and possibly massless) neutral particle. The neutrino belongs to the family of leptons, the particles that interact through the so-called weak force. For this reason...more

## Tools for Math and Science

Some concepts are used in many different fields of science and serve as a general purpose "toolbox" that helps us understand and manipulate ideas across disciplines. These "tools for math and science"...more

## Mechanics

Mechanics is the term used to refer to one of the main branches of the science of physics. Mechanics deals with the motion of and the forces that act upon physical objects. We need precise terminology...more

## Measuring Atmospheric Pressure

Even though we can't see air, it is real and is made of up many molecules which are zipping around at astonishing speeds. Air molecules travel about 1,090 mph at the surface of the Earth. That said, all...more

## Fundamental Forces

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...more

## Creating Elements up to Iron

When the temperature in the core of a star reaches 100 million degrees Kelvin fusion of Helium into Carbon occurs (three Helium nuclei combine to form a nucleus of Carbon). In the same range of temperature...more

## Binding Energy

A plot of the binding energy per nucleon vs. atomic mass shows a peak atomic number 56 (Iron). Elements with atomic mass less then 56 release energy if formed as a result of a fusion reaction. Above this...more

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