General Physics I:

Science is a systematic and brief study of nature. It gathers knowledge on the basis of testable explanations. It is constantly changing and evolving based on the new facts and discoveries. It is divided into two basic parts, living science and non-living science. Living science (also known as Biology) is further divided into two parts, Botany (plant science) and Zoology (animal science). Non-living science (also known as Physical Science) is also divided into two parts, Physics and Chemistry. Physics is the most fundamental science of nature. The word physics is taken from Greek word ’physis’ meaning nature. Physics deals with the properties of matter and universe. Chemistry deals with the constituents of matter. Physics is also classified into two parts, classical physics and modern physics. Classical physics roughly deals with the macroscopic world anything larger than atomic size and moving with relatively low speed. It is governed by Newtonian mechanics, Maxwell’s equations, and thermodynamical principles. Modern physics on the other hand is governed by quantum mechanics, statistical mechanics, and relativity. It explains that the matter and energy are alternate forms of one another. In general physics is divided into many branches such as mechanics, thermodynamics, electrodynamics, acoustics, optics, relativity, nuclear physics, and astrophysics.

Physics endeavors to decipher natural laws. In order to describe a natural law (or physical law) a measurement of varieties of physical quantities are essential. Measurement is a process that uses numbers and units to describe a physical quantity based on what can be observed. A physical property which can be quantified and measured in numbers is called a physical quantity. Length, mass, time, weight, temperature, density, speed, velocity, etc are physical quantities. Emotions, angers, feelings, appearances, etc. which can not be quantized are not considered as physical quantities. In order to measure physical quantities some standard measures (or standards) must be defined on which everyone can agree. Standards are special objects that are used to make measurements in terms of fixed units of measurement. We can measure things by compering them with the standards. Units of measurement provide standards for comparisons, so that the numbers from our measurements refer to the same thing. A meter stick is an example of a standard. When something is measured with a meterstick, we compare their similar property with the meterstick. For example, if we measure a height of a pillar with a meterstick and found that height to be 6 meter then 6 is a number of times meterstick used in the measurement and meter is a unit (or length) of meterstick. This makes measurement easier and uniform.