What Are the Four Fundamental Forces in Physics?
The forces that occur all around the universe are called the universal forces. There are four types of forces also called the 4 fundamental forces.
These Four Forces of Physics Are Called Universal Forces. They Are as Follows:
Strong nuclear force
Electromagnetic force
Weak nuclear force, and
Gravitational force.
Where a strong nuclear force is the strongest, and gravity is the weakest. The strong force has an effect on small distances, while gravity acts over large distances.
On this page, we will learn about four types of forces in detail.
Do You Know?
For a very long, scientists have been trying to combine all the forces into a single force.
However, in 1864, a Scottish scientist in the field of mathematical physics named James Clarke Maxwell FRSE FRS was able to combine the electrical and the magnetic forces into the electromagnetic force under Maxwell's equations.
Scientists also combined the electromagnetic and the weak force into the electroweak force but could not combine any of the other forces so far.
Four Forces in Physics
The fundamental forces a.k.a fundamental interactions of physics. These are the ways in which individual particles interact with each other.
It is results that every single interaction found taking place in the universe can be broken and described by the following four types of interactions:
Gravity
Electromagnetism
Weak Interaction or a Weak Nuclear Force
Strong Interaction or a Strong Nuclear Force
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Gravity
Out of the 4 fundamental forces, gravity has the farthest reach but has weak magnitude.
It is a purely attractive force that can reach the empty space in which two masses joined by an imaginary line attract toward each other. This invisible force keeps the planets orbiting around the sun and the moon around the Earth.
Gravitation is characterized as the theory of general relativity, which defines it as the curvature of spacetime around an object of mass. This curvature, in turn, creates a condition where the path of least energy passes towards the other object.
Electromagnetism
Electromagnetism is the combination of electricity and magnetism. It is an interaction of particles with an electrical charge. Statically charged particles interact through electrostatic forces, while charged particles in motion interact through both electrical and magnetic forces.
Do You Know?
For a very long time, after uniting the electric and magnetic forces into electromagnetic forces, in the 1940s, quantum electrodynamics is formed by the unity of electromagnetism with quantum physics.
Electromagnetism has been referred to as the most prevalent force in the world because it can affect things at a reasonable distance and with a fair/huge amount of force.
Weak Nuclear Force
The weak interaction seems to be a weaker force; however, it is a very powerful force that acts on the scale of the atomic nucleus. It is responsible for the occurrence of phenomena such as beta decay.
It has been combined with electromagnetism as a single interaction called the electroweak interaction.
Here, the weak interaction is mediated by the W boson, which is two types, viz: W+ and W- bosons, and also the Z boson.
Strong Nuclear Force
The strongest of all the forces is the aptly-named strong interaction; this force keeps nucleons, i.e, protons and neutrons bound together.
For example, in the helium atom, strong enough is needed to bind two protons together even though their positive electrical charges cause them to repulse each other.
In nutshell, the strong interaction allows particles like gluons to bind together, quarks to create the nucleons in the first phase.
Gluons can easily interact with other gluons, which gives the strong interaction at a theoretically infinite distance, although its significant events occur at the subatomic level.
Four Types of Forces
The below table enlists the properties of 4 fundamental forces
Properties of Fundamental Forces
Unification of Fundamental Forces
Many physicists believe that all 4 fundamental forces are, in fact, the versions of a single underlying unified force that has yet to be discovered.
Just like electricity, magnetism united to form electromagnetism, similarly, the weak force was unified into the electroweak interaction, they work to unify all of the fundamental forces.
Sir Isaac Newton realized that the gravitational force described an apple falling from the tree can also describe the moon’s orbit around the Earth.
Later in the 20th century, Steven Weinberg, Abdus Salam, and Sheldon Lee Glashow discovered that at higher energies, the electromagnetic force and the weak force combine to form a single electroweak force.
The work on unifying gravity with the other three fundamental forces is called quantum gravity. It suggests the existence of a virtual particle called the graviton that would be the mediating element in gravity interactions. To date, gravitons are imaginary particles, and no theories of quantum gravity have been adopted universally.
FAQs on Universal Forces: Types, Properties & Unification
1. What are the four fundamental universal forces in physics?
The four fundamental universal forces are the basic interactions that govern how matter behaves. They are believed to be the foundation upon which all other forces are based. The four forces are:
Gravitational Force: The universal force of attraction between any two objects with mass.
Electromagnetic Force: The force that acts between electrically charged particles.
Strong Nuclear Force: The force that binds protons and neutrons together within an atom's nucleus.
Weak Nuclear Force: The force responsible for the radioactive decay of subatomic particles. For a detailed explanation, you can refer to an overview of fundamental forces in nature.
2. Can you provide a real-world example for each of the four fundamental forces?
Certainly. Here are real-world examples that illustrate the action of each universal force:
Gravitational Force: The force that keeps the planets in orbit around the Sun and holds you to the Earth.
Electromagnetic Force: The force behind static electricity (like a balloon sticking to a wall after being rubbed), magnetism, and the chemical bonds that hold molecules together.
Strong Nuclear Force: This force is what holds the nucleus of an atom together, overcoming the immense electrical repulsion between positively charged protons.
Weak Nuclear Force: It plays a key role in nuclear fusion reactions that power the Sun and is responsible for certain types of radioactive decay, like beta decay.
3. How do the four fundamental forces compare in terms of strength and range?
The fundamental forces vary dramatically in both their strength and the distance over which they are effective:
Strong Nuclear Force: This is the strongest of all forces, but it has a very short range, acting only within the size of an atomic nucleus.
Electromagnetic Force: It is weaker than the strong force but has an infinite range, although its strength decreases with distance.
Weak Nuclear Force: This force is weaker than both the strong and electromagnetic forces and has an extremely short range, even smaller than the strong force.
Gravitational Force: This is by far the weakest force, but like the electromagnetic force, it has an infinite range. Its weakness is why we only notice it with very massive objects like planets and stars.
4. What distinguishes a fundamental force from other forces we experience, like friction or tension?
A fundamental force is a basic interaction that cannot be described in terms of other forces. Forces like friction, tension, and air resistance are not fundamental; they are considered 'emergent' or 'contact' forces. These forces arise from the complex electromagnetic interactions between the atoms and molecules of the surfaces in contact. For instance, friction is the result of countless tiny electromagnetic attractions and repulsions between the atoms of two surfaces rubbing against each other. Therefore, most everyday forces are manifestations of the fundamental electromagnetic force.
5. Why is gravity considered a universal force, even though it is the weakest?
Gravity is considered a universal force for two main reasons. First, it affects all objects with mass or energy, without exception. Second, it has an infinite range. While it is the weakest force on a subatomic scale, its effects become dominant on a large, cosmological scale. Because it is always attractive and has an infinite reach, the gravitational pulls of massive objects like planets, stars, and galaxies add up to shape the structure and motion of the universe. This is explained by the Universal Law of Gravitation.
6. How do universal forces govern the structure of the universe from atoms to galaxies?
The universal forces work together at different scales to build the universe we see:
At the smallest scale, the Strong Nuclear Force binds protons and neutrons to form atomic nuclei.
The Electromagnetic Force binds electrons to nuclei, forming atoms, and then binds atoms together to create molecules, which make up all substances.
The Weak Nuclear Force governs radioactive decay and fusion processes inside stars, creating heavier elements.
At the largest scale, the Gravitational Force pulls matter together to form planets, stars, and entire galaxies, dictating their orbits and large-scale structure.
7. Are the four fundamental forces related to each other?
Yes, physicists believe the four fundamental forces are different manifestations of a single, underlying force. At the high energies of the early universe, the electromagnetic and weak forces merge into a single electroweak force. Scientists are working on a Grand Unified Theory (GUT) to also incorporate the strong nuclear force. The ultimate goal is a 'Theory of Everything,' which would unite all four forces, including gravity. This concept is explored in the Unified Field Theory.
