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What is Physics


Table of contents

Introduction to What is Physics

Physics originates from a Greek word phusis, which means nature and phusike which means knowledge of nature. So, physics can be defined as the study of nature and the natural phenomena which can be seen around us. Physics provide us answers for why questions rather than what and thus it explains the scientific, systematic facts based on the concepts of physics. Physics tell us how things happen and also the reason behind each phenomenon and thus it explains each and every fact. The main goal of physics is to understand the universe around us. This may range from tiny molecular particles to huge entire solar system.

The knowledge in physics may increase as time passes as the new discoveries and inventions may replace the old concepts if proven to be accurate.



We can also say that physics is applied mathematics. In physics, we takes those tools which we have learnt in mathematics class and will finally apply them to solve the real scenario problems. We may study a variety of facts like energy, force, light, movement etc. Through physics we could examine how matter moves through space and time and also how it affect things like energy and force. Both chemistry and biology rely on the laws of physics to perform various calculations.

History of Physics

We believe that the ancient Greeks are the founders of early Physics. The following scientists contributed very much in the field of physics. Aristotle believed that almost all the things are made up of four elements which are air, water, fire and earth. He also felt that there are two types of motion which are natural motion and violent motion. Archimedes discovered the principle of density and buoyancy and also defined the concept of the center of gravity. Democritus observed that matter can be divided tiny small particles called Atoms. Galileo Galilei studied the behavior of falling objects thus formulated laws that covers their behavior. He experimented with pendulum and then used them in clocks.

Four elements by Aristotle

Four elements by Aristotle 

Johannes Kepler found out that the planets in the space follow an elliptical orbit and so the motion of these planets could be represented in mathematical equation. He the used this to predict the motion of the planets. The law of Kepler is still used in calculating the flight paths. Robert Boyle formulated one law of gas and thus he stated a relationship between pressure and volume at constant temperature.

Sir Isaac Newton formulated the laws of motion and universal gravitation. He also discovered the nature and composition of life. Later Benjamin Franklin found out that lightning was electrical by doing the famous kite experiment. Michael faraday discovered that magnets can be used to produce electric current and this gave rise to electric generator. Thus electromagnetic induction is his one of the finest discovery.

James Joule analyzed the nature of heat and established the relationship to mechanical energy. He then collaborated with Lord Kelvin in the formulation of absolute scale of temperature and carried out extensive research in magnetostriction. Magnetostriction is a property of ferro magnetic material that makes them modify their shapes when it is exposed to magnetic field. Thomas Young discovered the interference of light and thus substantiating the wave theory of light. He also discovered the way in which the lens of the eye changes the shape to focus on objects at different distances.

Electromagnetic induction

Electromagnetic induction

James Clark Maxwell worked on electromagnetism and formulated equations on electromagnetic field. Maxwell has also made significant contributions to the development of kinetic theory of gas. Wilhelm Roentgen made experiments with cathode rays rejection emitted in a low – pressure glass tube when voltage is applied between two metal plates. It was him who discovered the X-rays. Henri Becquerel discovered the radio activity.

Marie Curie and Pierre discovered two new elements which are Radium and Polonium. Marie Curie found that the harmful properties of X- rays are able to kill tumors. Max Planck went through the ultra – violet catastrophe. In solving the catastrophe he mentioned that light can be considered as discrete packets of energy which is called quanta. He then formulated the quantum theory which is basis of quantum mechanics. Albert Einstein introduced the theory of relativity. He is also known for the discovery of law of the photo – electric effect.

We know that physics impacts our daily lives. The inventions like computers, smart phones were invented by following the laws of physics which studies electricity. Motor vehicles are invented when the scientists found out the possibility of converting fuel into kinetic energy. The machines in medical care field like X-rays, ultrasounds are all created by considering the principles of light and electricity.

Physics and Scientific Methods

Science is a continually ongoing process. Scientific methods are a set of procedures that scientists follow to gain knowledge about the universe. It is a process or the steps taken to produce the reliable results for answering a specific question. The steps include Observation, Research, Hypothesis, Experimentation and Conclusion.

Observation is a statement of knowledge which is gained through the senses or also through the use of scientific equipment. All that can be observed with our five senses are included in the observations. Observations are necessary for collecting data. Research is an important step too as it may answer other questions we have and also help refine the experiments. We should use the reliable sources to learn background information.

Once the research is completed we can form the hypothesis which is a prediction of what we believe will occur. The word hypothesis actually means a possible solution to a problem which is based on knowledge and research. Experiments are investigations done that is intended to prove or disprove a hypothesis. An experiment is a tool that you design to find out if the ideas about the topic are right and wrong. Through experiments we collect two types of data which are qualitative and quantitative. Qualitative data relies on descriptive data and quantitative data relies on numbers. Once the results are in we need to analyze the data and thus need a form a conclusion.

 We may compare the results of the experiments conducted to the predictions posed by the hypothesis. Thus we will find out whether the hypothesis is was correct and thus sums up the findings. Conclusion is the summary of the experiment’s results, and how those results match up to our hypothesis. It is a statement of whether the original hypothesis was supported or refused by the observations and data collected.

Scientific methods

Scientific Methods

Various Classification and Branches of Physics

Physics can be broadly classified into three. They are classical physics, quantum physics and relativity. It was Sir Isaac Newton who introduced classical physics. Newton’s law of motion describes the motions of different bodies. His law of universal gravitation described the motion of planets and the falling of objects on earth. He invented a mathematical tool called calculus which is used many years for deriving new physics.

Isaac Newton has made contribution in the field of optics which deals with the study of light. The different phenomena of light are explained in optics. These principles are then used to focus light in telescopes, cameras and microscopes. Telescopes has enabled to see in to the depths of space and observe the wild array of objects and thus astrophysics and cosmology came into existence. James Clark Maxwell discovered the light is an electromagnetic wave. He then brought the concept of electromagnetism. We know that electromagnetism explains electricity too. The electromagnetism branch deals with the observations, principles, laws and methods that relate electricity and magnetism.

Classical Mechanics is related to Newton’s laws and it also includes the properties and motion of solid objects, the movement of objects when a force is applied etc. Fluid Mechanics deals with the flow of liquids and gasses. Thermodynamics is the description of energy and how it passes from one form to another.

Albert Einstein developed the theories of relativity. It mentions that energy and matter are different aspects of the same thing. In quantum physics the atomic theory probed the nature of the atom, and then we had more details regarding the atom. Condensed matter physics tells about the quantum physics of many atoms which are together in solids and liquids and finally evolved great technologies like computers, lasers etc.

Nuclear Physics describes the behavior of nucleus and it also tell us about the radiation, nuclear fission, the splitting of the atoms which are used in nuclear power plants and nuclear fusion. Particle physics deals with the fundamental sub atomic particles. The quantum field theory captures all of quantum physics and combines it with the special theory of relativity.

Branches of Physics

There are different branches for physics. Mechanics is a branch of physics that deals with the motion and force that produces motion. The branch astrophysics is the physics in the universe that includes the properties and interactions of celestial bodies in astronomy.

The Atomic physics is a branch of physics that deals with the structure and properties of the atom. The Nuclear physics deals with the structure, properties and also the reaction of nuclei of atoms. The branch of physics that is dealing with the structure and properties of solid materials is the solid-state physics. The plasma physics is one branch of physics that deals with the properties of highly ionized atoms that forms a mixture of bare nuclei and the electron.

The bio-physics is the branch of physics that deals with the application of physical methods and explanation to bio – physics systems and structures. The branch of mechanics dealing with the mathematical description of the motion and interaction of sub atomic particles, particle – wave duality, incorporating the concepts of quantization of energy and the uncertainty principle is quantum mechanics.

The study of physics has led to all kinds of inventions we use in our daily lives. Thus, in physics we will be learning about the fundamental laws of nature. It’s the way we understand the nature in a scientific way.


  • The branch of science that deals with the study of nature and natural phenomena is called Physics. We will also learn the fundamental laws of nature. Physics is derived from the word Phusis which means nature. Phusike means knowledge of nature.

  • Physics provide us details about how things happen and the reasons behind each phenomenon and thus we can understand the universe around us.

  • Physics is applied mathematics.

  • The ancient Greeks are the founders of early Physics.

  • Many scientists have contributed very much in the field of physics.

  • The steps in a scientific method include Observation, Research, Hypothesis, Experimentation and Conclusion.

  • Physics can be broadly classified into three and they are classical physics, quantum physics and relativity. Branches of physics include Mechanics, astrophysics, Atomic physics, Nuclear physics, plasma physics, bio-physics, Electromagnetism etc.

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