Unit 9: Nature of Science — Long Questions

Scope of physics (i) Physics is the fundamental science that deals with the constituents of the universe, that is, matter, energy, space, time and their mutual relationships and interaction.
(ii) It strives to understand how the universe works, from the smallest subatomic particles to the largest star and galaxies. You have studied some of the basic properties of matter, energy and their mutual inter-relationship in the earlier chapters of this book. We will discuss with some details the concept of space and time in the higher classes.
(iii) Briefly, the space is the three-dimensional extent in which all objects and events occur. It provides framework to define positions and motions of various objects under some force.
(iv) The time measures the sequence and durations of events. It is considered fourth dimension. For example, oscillating motion such as that of a swinging pendulum relies on the time interval that determine frequency of oscillations. Another example is the time dilation which is a phenomenon discussed by ultra-high speed compared to one relatively at rest.
(v) Physics explores how these fundamental aspects are inter connected. For example, the theory of relativity explains how space and time are not absolute quantities but are related to each other. It describes the relationship between space and time and how they are influenced by gravity and speed, for example the bending of light around massive objects like stars.
(vi) Another branch of physics, the quantum mechanics, explains the behavior of particles at the atomic and subatomic levels. It is how the physics has applied its principles to wide variety of phenomena, from everyday occurrence such as related to motion and heat to the extreme conditions found in the universe.

Branches of Physics Due to expanding scope of research in Physics, it is usually divided into following branches.
i. Mechanics:
It is study of motion and the physical effects which influence motion. It is based on Newton's laws of motion and gravitation and is often called classical mechanics.
ii. Heat and Thermodynamics:
It deals with the thermal energy possessed by the materials and its used when it flows from one body to another. It may be called as thermal physics.
iii. Acoustics:
It deals with the nature and physical aspects of audible sound energy. The wide range of applications of sound properties are studied in the field of acoustics.
iv. Optics:
It deals with the physical aspects of visible light.
v. Electromagnetism:
It is the study of electromagnetic phenomenon and mutual relationship between electric current and magnetic field.
vi. Quantum Mechanics:
It explains the behavior of particles at the atomic and subatomic level.
vii. Relativistic Mechanics:
It explains how space and time are not absolute quantities but related to observer. It describes the relationship between them and how they are influenced by gravity and speed.
viii. Nuclear Physics:
It is the study of the properties of nuclei of the atoms and particles within the nuclei.
ix. Particle Physics:
It is the study of subatomic particles and elementary particles which are basic building blocks of matter.
x. Astronomy:
It is study of distribution of celestial bodies like planets, stars and galaxies.
xi. Cosmology:
It explores the large structure and evolution of the universe.
xii. Solid State Physics:
It is the study of some specific properties of matter in solid form.

Interdisciplinary Nature of Physics It refers to integration and interaction of Physics with various other fields of study. Physics, being fundamental science, provides essential principles, techniques and methods that are applicable across a wide range of disciplines.
i. Bio Physics:
Some biological systems and processes are described using the principles and techniques of physics under this field of Study. Examples include the mechanics of biological structures, physical properties of cells, tissues and organs.
ii. Medical Physics:
It applies physical principles to develop techniques and technologies for health diagnosis and treatment. The examples include imaging techniques, such as X-rays; ultra sound MRI and CT scan and also radiation therapy for cancer treatment.
iii. Astrophysics:
It deals with the physical properties and processes of celestial bodies and phenomena. For example, the interaction between the matter and energy in space to understand the universe as a whole.
iv. Geophysics:
It applies physical principle to the study of internal structure of the Earth, its magnetic and gravitational fields, seismic activity (earthquake) and volcanoes etc.
v. Climate Physics:
It includes the study of physical process in the environment, including atmospheric dynamics climate change and weather condition.
vi. Computation Physics:
It is about the use of computational techniques and methods to solve complex physical problems.

Interdisciplinary Research Collaboration and interdisciplinary nature of science is essential for addressing the complex issues and challenges of today and fostering innovation. By working together and sharing knowledge, scientist can achieve more significant breakthrough and contribute to a deeper understanding of the natural and physical world around us. It allows us to contribute to advance in technology, healthcare, environmental issues and many other areas. We need collaborated efforts because:
i. Solution of complex issues require multifaceted expertise.
Many challenging issues, such as climate change, disease prevention and treatment, sustainable energy solution are of diverse nature. It is difficult for one climate change requires knowledge for meteorology, oceanography physics, chemistry, biological and environmental sciences. Similarly, the health care issues such as recent Covid epidemic involved combined efforts of expertise from biology, chemistry, physics, medical technologies and data science to combat this challenge.
ii. Interdisciplinary approaches foster innovation:
Combined different perspectives and methodologies evolve innovation or out of box solutions. This approach can lead to novel insight and breakthroughs that might not emerge working in isolation. For example, Nano-technology is a blend of physics, chemistry, material science and engineering to create materials and devices at the Nano-scale with unique applications in development involves computer science, mathematical logic, neuroscience etc. The collaboration across these fields enhanced the development of intelligence systems and their application.
iii. Rapid sharing of knowledge and information across the globe:
Sharing and collaboration of knowledge across the globe brings rapids advances in science. The online internet information exchanges, conferences and workshops provide platforms bringing together researchers from different fields to share their fresh finding, discussion and brainstorming new approaches. Collaborated research projects and research journals are also means of collaborate research.
Interdisciplinary research and collaboration leads to a more holistic understanding of challenging issues by interacting with different perspectives such as that of environment and space exploration.

Scientific Method Scientific method is a systematic approach used to search for truth of an issue and problem solving regarding natural and physical world. It is based on the following steps.
i. Identify or recognize an issue or a problem.
ii. Gather information through observation of its various aspects.
iii. Propose and explanation or a guess work known as hypotheses.
iv. Perform experiment or collect evidences to test the hypothesis.
v. Record, organize and analyze gathered data, plotting and interpreting graphs to reach at a conclusion which is called a theory.
vi. Repeated tests of the theory to wide range of similar issues then lead toward the formulation of a law.
Some key steps are elaborated here.
i. Observation:
The first step in scientific method is to make observations of natural processes and to collect the data about them. This may be done either by ordinary observations or by obtaining the results from different experiments. For example, it is our common observation that shadow of an opaque object is formed when it is placed in the path of light coming from the Sun or a lamp (Fig. 9.1).
ii. Hypothesis:
On the basis of the data collected through observations or experimentation, we can develop a hypothesis. This is done in order to test its logical results, i.e., it is assumed that nature will act in a particular way under shadows of opaque objects are formed when they come in the path of light because light travels in a straight line.
iii. Experiment:
Experiment is an organized repeatable process which is used to test the truth of a hypothesis.
To verify the assumption made in the above example, four card boards, each with a hole, are placed in a straight line, such that the hole in 1st card is in front of a torch. When we see through the hole in cards, we can see the light of the torch (Fig. 9.2-a). If any of these cards is displaced, we cannot see light passing through (Fig. 9.2-b). Thus this experiments proves that light travels in a straight line.
iv. Theory:
After the successful verification of an assumption and with the help of careful experimentations, it becomes a theory and is applicable to similar phenomena. With the help of the above experiments, the assumption has been proved that light travels in a straight line. So it then becomes a theory.
It is a logical explanation of the causes and effects of an issue or an event that occurs in nature.
v. Prediction:
After the careful analysis of a theory we can make predictions about certain unknown aspects of nature. To verify the prediction, experiments are designed to test the theory over and over again. If test result does not agree, hypothesis is changed or rejected.
vi. Falsifiability:
It is a concept introduced that suggests theory to be considered scientific if it also make predictions that can be tested and potentially proven false. The requirement of falsifiability ensures that theories are not based on vague, non-specific or untestable claims. It distinguishes scientific theories from false or pretended beliefs that cannot be experimentally tested.
vii. Law:
When a theory has been tested many times and generally accepted as true, it is called a law. The law is such a statement regarding the behavior of nature which explains the observations and experiments of the past and can predict about other aspects of nature. From the fact that light travels in a straight line, we can predict that shadow of an opaque object, similar in shape, is formed whenever it is placed in the path of light. For example, the shadow of a ball will be round whereas the shadow of a rectangular block will be a rectangle. After testing the theory under different situation, this becomes a law of science that light travels in a straight line.
The theories or laws of physics are man-made ideas about the way the things work. They are liable to be disproved or modified with the future advances in science which brings fresh facts and new insights about the natural and physical world.