Secondary 4 Physics Introduction

1. Secondary 4 Physics Introduction Dear S.4 physics students, I highly recommend you to read this PowerPoint file before attending your first physics lesson in 2003 – 2004. Mr. Ma 

2. Introduction to Physics • What is Physics ? • Why do we study Physics ? • Content of HKCEE Physics • How can we study Physics well ? • Basic mathematical skills: Treatment of significant figures and Graphs For any problems, send an e-mail to Mr. Ma at olc-mkl@hkedcity.net

3. What is Physics ? • Physics is the quantitative (that is, involving “data analysis”) study of the laws of nature (大自然定律) using scientific methods. • We learn physics based on (1) Experimental work: It provides us with raw data, then we look for relations among the data, and try to guess general laws. (2) Theoretical (理論的) work: To apply the physical laws to different situations and hence solve problems. For any problems, send an e-mail to Mr. Ma at olc-mkl@hkedcity.net

4. Why do we study physics ? 1. To satisfy our curiosity about nature 2. To provide us with a good training in working systematically and scientifically (I am sure that you would agree with this advantage of studying physics. I hope you will enjoy learning physics !) 3. To upgrade our living standard, because grasping physics (as an important branch of Science) -> high Technology -> better living in the Society For any problems, send an e-mail to Mr. Ma at olc-mkl@hkedcity.net

5. Content of S.4 – S.5 Physics 1. Mechanics (力學) - a study of motion: e.g. What can you say about the motion of a falling object ? 2. Heat (熱學) l           - a study of heat transfer: e.g. What is the final temperature if a cup of water at 20oC mixes with another identical cup of water at 400C ? 3. Waves (波動學) - a study of wave motion (which is one way of energy transfer), e.g. radio waves, water waves 4. Electricity (電學) & magnetism (磁學) 5. Atomic Physics (原子物理學) - a study of atomic structure and radioactivity For any problems, send an e-mail to Mr. Ma at olc-mkl@hkedcity.net

6. How to study physics better ? • After learning some physics, ask yourself : • What are the aims (目標) of that chapter ? • What tools and methods have you got to achieve the above aims ? • - Tools mean “physical quantities”, e.g. time. • - Methods mean “physical laws”, “experimental • approach”, “logical thinking skills” and • “mathematical skills”. • Practise more in solving problems, and try to ask more questions from the problems: • e.g. If a problem is related to a “falling” ball, you may ask “what happens when the ball is rising ?”. For any problems, send an e-mail to Mr. Ma at olc-mkl@hkedcity.net

7. Basic mathematical skills:Treatment of significant figures 1.The number of significant figures reflects the accuracy of a measurement. 2.The final result is governed by the least accurate measurement. Example: The volume of a rectangular block is: V = abc, where a, b and c are its length, width and height respectively. Let a = 15.70 cm, b = 4.80 cm and c = 2.0 cm. Find V. Solution: When we calculate 15.7 x 4.8 x 2 by using a calculator, it displays 150.72. Then, is V equal to 150.72 ? NO, because the least accurate measurement is “c” (only 2 sig. fig.), so V should be expressed in 2 sig. fig. Hence, V = 150 cm3(corrected to 2 sig. fig.). For any problems, send an e-mail to Mr. Ma at olc-mkl@hkedcity.net

8. Basic mathematical skills:Graphs p y x q y is directly proportional to x. p increases linearly with q. For any problems, send an e-mail to Mr. Ma at olc-mkl@hkedcity.net

9. Basic mathematical skills:Graphs y y 1/x x y is directly proportional to 1/x. y is inversely proportional to x. For any problems, send an e-mail to Mr. Ma at olc-mkl@hkedcity.net