ClearIAS » Science and Technology Notes » The Four Fundamental Forces of Nature
Last updated on by Alex Andrews George
The Four Fundamental Forces of Nature are Gravitational force, Weak Nuclear force, Electromagnetic force and Strong Nuclear force.
The weak and strong forces are effective only over a very short range and dominate only at the level of subatomic particles.
Gravity and Electromagnetic force have infinite range. Let’s see each of them in detail.
Table of Contents
The Four Fundamental Forces and Their Strengths
- Gravitational Force – Weakest force; but has infinite range. (Not part of the standard model)
- Weak Nuclear Force – Next weakest; but short range.
- Electromagnetic Force – Stronger, with infinite range.
- Strong Nuclear Force – Strongest; but short range.
Gravitational Force
The gravitational force is weak but very long-ranged. Furthermore, it is always attractive. It acts between any two pieces of matter in the Universe since mass is its source.
Weak Nuclear Force
The weak force is responsible for radioactive decay and neutrino interactions. It has a very short range and. As its name indicates, it is very weak. The weak force causes Beta-decay ie. the conversion of a neutron into a proton, an electron, and an antineutrino.
Electromagnetic Force
The electromagnetic force causes electric and magnetic effects such as the repulsion between electrical charges or the interaction of bar magnets. It is long-ranged but much weaker than the strong force. It can be attractive or repulsive and acts only between pieces of matter carrying an electrical charge. Electricity, magnetism, and light are all produced by this force.
Strong Nuclear Force
The strong interaction is very strong but very short-ranged. It is responsible for holding the nuclei of atoms together. It is basically attractive but can be effectively repulsive in some circ*mstances. The strong force is ‘carried’ by particles called gluons; that is, when two particles interact through the strong force, they do so by exchanging gluons. Thus, the quarks inside of the protons and neutrons are bound together by the exchange of the strong nuclear force.
Note: While they are close together the quarks experience little force, but as they separate the force between them grows rapidly, pulling them back together. To separate two quarks completely would require far more energy than any possible particle accelerator could provide.
Electroweak Theory and Grand Unification Theories (GUT)
There is speculation, that In the very early Universe when temperatures were very high (the Planck Scale) all four forces were unified into a single force. Then, as the temperature dropped, gravitation separated first and then the other 3 forces separated. Even then, the weak, electromagnetic, and strong forces were unified into a single force. When the temperature dropped these forces got separated from each other, with the strong force separating first and then at a still lower temperature the electromagnetic and weak forces separating to leave us with the 4 distinct forces that we see in our present Universe. The process of the forces separating from each other is called spontaneous symmetry breaking.
- The weak and electromagnetic interactions have been unified under the Standard Electroweak Theory, or sometimes just the Standard Model. (Glashow, Weinberg, and Salaam were awarded the Nobel Prize for this in 1979). [Unification of Weak forces except for gravity]
- Grand unification theories attempt to treat both strong and electroweak interactions under the same mathematical structure. [Unification ofWeak forces and strong forces] PS: Attempts to include gravitation in this picture have not yet been successful.
- Theories that add gravity to the mix and try to unify all four fundamental forces into a single force are called Superunified Theories.
- PS: Grand Unified and Superunified Theories remain theoretical speculations that are as yet unproven, but there is strong experimental evidence for the unification of the electromagnetic and weak interactions in the Standard Electroweak Theory. Furthermore, although GUTs are not proven experimentally, there is strong circ*mstantial evidence to suggest that theory at least like a Grand Unified Theory is required to make sense of the Universe.
References
UPSC Prelims Question 2013
Qn: The known forces of nature can be divided into four classes, viz, gravity, electromagnetism, weak nuclear force and strong nuclear force. With reference to them, which one of the following statement is not correct?
- Gravity is the strongest of the four
- Electromagnetism acts only on particles with an electric charge
- The weak nuclear force causes radioactivity
- Strong nuclear force holds protons and neutrons inside the nucleus of an atom.
Ans: 1
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Reader Interactions
Comments
Sanju says This is not enough for understanding
Reply
- Deanna Graham says
Nice synopsis. Thank you.
Reply
- john ryan says
He contradicts himself.
“Gravity is the weakest force” , he says
Further down h states “gravity is the strongest force “Reply
- prasad says
it is weakest force but long range force responsible for stability between sun and earth
- Ten toes down says
Brother u have to read it says which one is a false statement 😂
- Mytht1c says
that was in a question, he asks which is false.
Reply
- Rodolfo Carrara says
In the four types of forces I did not find hydrodynamic forces, from waterfalls for example, so I think that this one is missing in the four types of natural forces. The question is: is this type of force derived or associated with one of the four types described in this classification?
Reply
- Garylee says
Re read.the question and notice the statement “not correct”.
Reply
- ayush says
movement of water is under gravitational force, so hydrodynamic force will come under application of gravity only.
See AlsoForced EquityReply
- Geno says
Hydrodynamic force is associated with gravity. No gravity, no waterfalls 😎
Reply
- Milaan says
The reason they call gravity a strong force because depending on circ*mstances gravity can overcome every forces ( black hole is a good example). The range of gravity is infinite so it results in simultaneous iteration among each bounded particles. On the other hand strong nuclear forces can interact with their neighbors only resulting into weaker overall effect.
Then you may say that electromagnetic forces should also dominate since it has infinite range. But, unlike gravity which is attractive only. EM forces are both attractive and repulsive. Also majority of things in universe is electrically neutral (or at least maintain local electrical neutrality). Moreover, when atoms are bounded together very strongly, they squeeze protons and electrons into neutrons diminishing the EM forces (that what happens in neutron stars).
Reply
- Linda says
Which force explains me raising my hand? (The force of muscle)
Reply
- anbfuhsdjf says
Electromagnetic force, as it is responsible for the electroc signals that contract the muscles
- Vincent J Petti says
What force is responible the change in energy when carbon and oxygen form CO2
Reply
- Kyle says
Hydrodynamic forces are a byproduct of gravity, albeit a substantial force (:
Reply
- Ron says
Your hand is raised by electromagnetism. Muscles use electrical forces to fire.
The same forces are involved in almost all chemical reactions (such as the change in energy as carbon and oxygen form CO2).Reply
- Linda says
Thank you, Ron.
Reply
- mohsin liaqat says
please give me ans ……can we describe all forces in a foundamental forces
Reply
- laura says
This was very helpful but I can’t use this as a source since I can’t find the author or the date this was published.
Reply
- Anuj says
You article on Fundamental Forces In Nature written very nicely
Reply
- Archana says
Hydrodynamic forces can be derived from the gravitational forces. These are the only 4 fundamental forces of nature
Reply
- KKR says
my question is related to these forces I want to ask that what will happen when these force go beyond control?
Reply
- Mushabe David says
How do strong interactions repulsive,in which way?, Thanks.
Reply
- M.pavan kumar says
Thank you sir🙏 but i never understood electromagnetic force
Reply
Leave a Reply
Greetings, enthusiasts of science and seekers of knowledge. I am here to delve into the intricacies of the Four Fundamental Forces of Nature, a subject that has captivated the minds of physicists and curious minds alike. My expertise in this domain is not just academic; it stems from a profound passion for unraveling the mysteries that govern our universe.
Now, let's embark on a journey through the concepts presented in the article about the Four Fundamental Forces of Nature.
Gravitational Force:
- Definition: The gravitational force is the weakest among the four forces but has an infinite range.
- Characteristics: Always attractive, it acts between any two pieces of matter in the Universe due to mass being its source.
- Notable Effect: Responsible for the stability between celestial bodies like the Sun and Earth.
Weak Nuclear Force:
- Definition: The weak force is the next weakest, operating over a short range.
- Role: Responsible for radioactive decay and neutrino interactions.
- Notable Effect: Causes Beta-decay, converting a neutron into a proton, an electron, and an antineutrino.
Electromagnetic Force:
- Definition: The electromagnetic force is stronger than the weak force and has infinite range.
- Effects: Causes electric and magnetic effects, such as repulsion between electrical charges and interaction of bar magnets.
- Applications: Electricity, magnetism, and light are produced by this force.
Strong Nuclear Force:
- Definition: The strong interaction is the strongest but acts over a short range.
- Role: Holds the nuclei of atoms together, being attractive but sometimes effectively repulsive.
- Particle Carrier: Carried by particles called gluons; quarks inside protons and neutrons are bound together by the exchange of the strong nuclear force.
Electroweak Theory and Grand Unification Theories (GUT):
- Historical Speculation: In the early Universe, at high temperatures, all four forces were unified into a single force.
- Separation Process: Gravity separated first, followed by the separation of the weak, electromagnetic, and strong forces.
- Unification Theories: Electroweak Theory unifies weak and electromagnetic interactions. Grand Unification Theories attempt to unify strong and electroweak interactions.
- Symmetry Breaking: The process where forces separate from each other is called spontaneous symmetry breaking.
Superunified Theories:
- Definition: Theories attempting to unify all four fundamental forces into a single force.
- Status: Speculative and unproven, with attempts to include gravity still not successful.
- Circ*mstantial Evidence: While not proven experimentally, there is strong circ*mstantial evidence suggesting the need for a Grand Unified Theory to make sense of the Universe.
In conclusion, these Four Fundamental Forces govern the workings of our universe, each playing a crucial role in maintaining cosmic order. The quest for a unified theory continues to be a tantalizing challenge for physicists, with theories like Superunified Theories pushing the boundaries of our understanding.
