What is Physics?

  • Helena Kudiabor
  • May 15 2024

Physics is the branch of science that explores how and why the universe works. From the tiniest subatomic particles, to the largest planets in our solar system, physics is crucial to our understanding of the world we live in. This article will tell you everything you need to know about physics, from the discoveries and theories that shaped our modern world, to the exciting opportunities available for those interested in the field.


Branches of Physics

Physics can be divided into two sections: classical and modern. Classical refers to research conducted before 1900, while modern physics build on classical theories.

Classical physics:

  • Mechanics: The study of movement, and how laws of motion and force apply to physical objects.
  • Electromagnetism: The electric and magnetic interactions that happen between charged particles.
  • Thermodynamics: The study of heat and the laws governing it
  • Acoustic: The properties and behaviour of sound waves

Modern physics:

  • Quantum: The study of subatomic particles (the particles that make up atoms)
  • Relativity: How space and time are interconnected, and the role of gravity in this relationship
  • Nuclear: The structure and function of the atom’s core (known as the nuclei)
  • Atoms: The structure, behaviour and function of individual atoms.

Fundamental forces and interactions

A key factor that underpins physics is the idea of the fundamental forces. Physicists argue these four fundamental forces - gravity, electromagnetism and the strong and weak nuclear forces - are crucial to shaping the universe we inhabit:

Gravitational force: Gravity is an attractive force that draws two objects together: without it the Earth wouldn’t stay orbiting around the sun and we wouldn’t be able to keep our feet on the ground. Even though it’s the weakest of the fundamental forces, gravity’s ability to work across infinite distances means it’s crucial for holding the universe’s structure.

Electromagnetic force: This acts between charged particles, like positively charged protons and negatively charged electrons.When these particles interact, they generate electricity. However, once they begin to move, they begin to create a magnetic field, setting up the magnetism part of electromagnetism. 

Strong nuclear force: This is the strongest of the four fundamental forces, six thousand trillion trillion trillion times stronger than gravity. This is because it binds together the fundamental particles of matter (protons and neutrons) to form larger particles. It holds together the quarks (elementary particles) that make up protons and neutrons. 

Weak nuclear force: This is responsible for interactions between subatomic particles like protons, neutrons and electrons. It leads to particle decay, changing one type of subatomic particle into another.

Fundamental laws of physics

The fundamental laws of physics form the basis of our understanding of various physical phenomena. Some of the most important laws include: 

Newton’s law of motion: Newton’s laws of inertia, acceleration and action-reaction laid the foundation for our understanding of motion.

Maxwell’s equations: James Clerk Maxwell provided a foundation for the study of electromagnetism through his equations describing the behaviour of electric and magnetic fields.

Theory of relativity: Einstein’s special theory of relativity and general theory revolutionised our understanding of space, time and gravity.

Laws of Thermodynamics: The four laws of thermodynamics govern the transfer of energy and how temperature impacts matter. 

Laws of Conservation: These state the energy cannot be created or destroyed, but can be transformed from one form to another. As a result, the amount of energy in the universe remains constant.

Why is physics important?

Without physics, the modern world would be very different. Our understanding of forces and motion has allowed us to build safe and effective cars, trains and planes. Similarly, the discovery of electromagnetism means we can now harness the power of electromagnets for MRI machines, loudspeakers and many other electronic devices. 

The interdisciplinary nature of physics has allowed the discipline to positively influence a range of fields. For example, the healthcare sector utilises physics theories to improve diagnosis and treatment of disease and illness. Physics has played a crucial role in the development of radiotherapy, as well as the fundamentals of medical imaging techniques like ultrasounds and X-rays. Engineers also draw heavily on physics theories to build and repair roads, electrical systems and numerous other structures.

Despite all the exciting innovations in physics, physicists are conducting new research all the time. Some particularly important topics in physics right now include the preparations to send humans to Mars, the development of artificial intelligence, the rise in renewable energy and the search for dark matter. 

Hopefully this article has given you some clarification on what physics is and why it’s so crucial to contemporary life. If any of the research or theories we’ve discussed in this article have piqued your interest, we encourage you to explore them further. You never know what could kick start a career or further study in physics!