Chapter 1 Measurements - Introduction

Introduction

The earlier observations of man about the world around him and facts about the natural phenomena and material things resulted in the birth of single discipline of science called "Natural Philosophy".

It is further classified into two main branches:

(1) Biological Sciences

"The sciences which deals with the study of living things are called Biological sciences."
Examples are: Biology, Zoology, Botany, etc

(2) Physical Sciences

"the sciences which deals with non-living things are called physical sciences."

Examples are: Physics, Chemistry, Astronomy, Geology, etc.

Introduction to Physics

"physics is an important and basic part of physical sciences." It is an experimental science, required and applicable to nearly all disciplines of science.

At present there are following three main frontiers of fundamental science:

1. The world of extremely large body - the universe itself - its birth and expansion by "The Creator", from a very special "Cosmic Egg", with temperature of millions of degrees (Big-Bang Theory), which probably started 20 billion years ago.
2. The world of extremely small particles such as electron, protons, neutrons and other sub-atomic particles.
3. The world of complex matter. It is also the world of "middle sized" things, from molecule at one extreme, and bodies on the earth and the earth on other extreme. This is fundamental physics, which is the heart of science.

What is Physics?

It is the branch of science which deals with the study of matter, energy and the relationship between them.

The study of physics involves investigating such things as the laws of motion, structure of space and time, the nature and type of forces that hold different materials together, the interaction between different particles, the interaction of electromagnetic radiation with matter and so on.

Physics up-to 1890 AD is called classical physics and physics after 1890 AD up-till now and on-wards is called modern physics.

A few branches of classical physics are:

1. Mechanics: This branch of physics deals with the motion of particles under the action of different forces.
2. Heat & Thermodynamics: This branch of Physics deals with the nature of heat, its measurement, measurement of temperature and conversion of heat energy into mechanical energy.
3. Electromagnetism: This branch of physics deals with the interaction of electricity and magnetism, their development and use in practical life.
4. Optics: This branch deals with the study of nature of light, its properties and about optical instruments of different types.
5. Sound: this branch deals with production nature and different properties of sound.
6. Hydrodynamics: This branch deals with the study of the motion of fluids (liquids & gases).

A few branches of modern physics are:

1. Special relativity: In this branch of physics we study about non-accelerated frames of reference. This was stated by Einstein in 1905.
2. General Relativity: In this branch we study about the accelerated frames of reference. This theory came in 1915 (by Einstein).
3. Quantum Mechanics: It is the mathematical theory based on Plank's quantum hypothesis.
4. Atomic Physics: This branch deals with the behavior, structure and nature of atoms.
5. Molecular Physics: In this branch we study about the structure of matter on the basis of molecules.
6. Nuclear Physics: In this branch we study about the atomic nuclei, nuclear reactions and radioactivity.
7. Solid State Physics: This branch is concerned with the structure and properties of solids.
8. Particle Physics: This branch is concerned with "elementary particles" of matter.
9. Superconductivity: This branch deals with the study of superconductors and their development.
10. Superfluidity: This branch deals with the behavior and nature of super fluids.
11. Plasma Physics: This branch is concerned with highly ionized gases at very high temperatures. Plasma is called forth state of matter.
12. Magnetohydrodynamics: This branch deals with the behavior of a conducting fluid under the influence of a magnetic flux.
13. Space Physics: This branch deals with different aspects of space.

Physics is most fundamental of all sciences and provides other branches of science, basic principles and fundamental laws. This overlapping of physics gave birth to new branches such as physical chemistry, biophysics, astrophysics, health physics etc.