Home / Topics / Particle Physics & Cosmology
Four fundamental forces
Beginner
Gravity, electromagnetism, weak and strong.
Gravity (weakest, infinite range), electromagnetism (infinite range), the weak force (10⁻¹⁸ m, beta decay) and the strong force (1 fm, binds quarks). Relative strengths 10⁻³⁸ : 1/137 : 10⁻⁶ : 1 roughly.
Gravity is 10³⁶ times weaker than electromagnetism between protons.
Gravity isn't yet part of the Standard Model.
In more detail
The four fundamental forces are gravity, electromagnetism, the weak nuclear force and the strong nuclear force. Each is carried by specific force-carrying particles.
Real-world uses
- Nuclear physics explains radioactive decay through the weak force.
- Chemistry depends on electromagnetic forces between electrons.
- Engineers and scientists treat electromagnetism as the force that holds atoms and molecules together and drives electronics.
Open the interactive lesson, with simulation and quiz →
Frequently asked questions
Which force is strongest?
The strong nuclear force, at short distances inside nuclei.
Which force is weakest?
Gravity, at the particle scale, though it dominates large objects.
Which force is the weakest?
Gravity is by far the weakest of the four forces at the scale of particles, though it dominates at large scales.