GSC101 Handouts Lectures 1-29 and 31-45

Summary of lecture # 1

Introduction to G. Science & System of Measurement

What is it that allows us to term Biology, Chemistry and Physics as sciences whereas literature, languages, history and art are not termed as sciences? The answer to this question is the reproducibility of the results is the basic difference between science and humanity. Science is something which deals with experimentation, has certain methods and procedures. We can better understand about reproducibility as whatever a person is saying another scientist or researcher in another laboratory can reproduce those results…for example we take a small piece of equipment, measure its length and reported that its length is 10 cm. Another person who has the same equipment can do this and confirm the result. In other words, we can say that under similar condition and circumstances will lead to the similar results. Science is basically means to look, observe and discover something. Scientific method is a method of procedure consisting in systematic observation, measurement, and experiment and the formulation, testing and modification of hypothesis. It is a just roadmap for the study of science itself. It is through this process of experimentation and refinement by which new scientific knowledge is generated. It is a process through which we explore, observe and experiment. Scientists use this to search the cause and effect relationship in nature as something is happen by something which is causing it. Hypothesis is nothing just a statement conveying that we observe something. Then we test that statement through experiment and get a set of results. Here we can reach at three conclusions: i. Hypothesis is correct and reported. ii. Hypothesis is partially correct and reported iii. Hypothesis is incorrect If we reach at result 2 or 3 then we again observe the facts, consult with actual results and keep testing until reach the actual result. All sciences obey two philosophical principals: 1. Principal of logic and 2. Search fort he truth. Physics is known as fundamental science as other sciences use the laws and principals of Physics. Physics deals with the study of properties of matter, energy and mutual relationship between them. The System International Units is system of units which is used for measurement of different thing internationally. Measurement system develops over centuries. The first measurement which is recorded is cubit. It is a measurement of length. It comes from ancient Egypt. It is the length of the tip of the finger to the bottom of the arm of a Firon. In SI Units, there are seven base units:

Base Quantity

Unit

Length Meter Mass Kilogram Time Second Current Ampere Temperature Kelvin Quantity of a substance Mole Luminosity Candela Besides the base unit we have two supplementary units: Plane angle radian Solid Angle Steradian Whenever two same units are added or subtracted, the final unit remains the same. But when two or more same units or different units are multiplied or divided, we have a new unit which is known as derived unit. For example area = length x breadth m2 = m x m Or Speed = distance travelled / time taken ms-1 = m/s Scientific notation is a method to write very small and very large umbers in powers of ten, e.g. 100,000,000 = 1 x 108 or 0.00002315 = 2.315 x 10-5. All the quantities in Physics need three things to be defined and four if we add the direction: a) A number telling us how much b) A unit telling us what the quantity is c) A prefix if the required quantity is very large or very small like megawatt or nanometer d) Direction Commom Prefixes 1. nano = 1x10-9 2. micro = 1x10-6 3. milli = 1x10-3 4. centi = 1x10-2 5. Kilo = 1x103 6. Mega= 1x106 7. Giga = 1x1012 Physics is divided into two main branches: Classical Physics and Modern Physics Classical Physics deals with mechanics, waves and light, heat and electricity and magnetism. Modern Physics deals with Quantum Mechanics and Atomic and Nuclear Physics. Mceanics is a branch of science which deals with the study of motion of objects. Mechanics is divided into two: Kinematics: It is a branch of Physics which deals with the study of motion of bodies without the influence of force. Dynamics: It is a branch of Physics which deals with the study of motion of bodies under the action of force. State of rest: A body is said to be in state of rest if it does not change its position with respect to its surroundings. e.g. a book on the table is at rest.