講者： 許永昌 老師 1

Contents Developing a Charge Model Charges and Materials Charges Atoms and Electricity Charge Conservation and Charge diagram (P795) Insulators and Conductors Charging and Discharging Charge polarization Electric Dipoles Coulomb’s law The Field Model Unit vector notation 先講電，再講電力，最後講到電場。 2

Action I ( 請預讀 P788~P790) 3

The conclusion thus far are: 4

Action II ( 請預讀 P791~P792) 5 Charge diagram Metal ball Insulator or conductor

Charge ( 請預讀 P793~P795) 6

The Micro/Macro Connection 7

Homework Student Workbook

Insulators and Conductors 9

Action III ( 請預讀 P797~P800) A piece of paper Metal balls: Separate them while rod is held closer.

Stop to Think 11

Homework Student Workbook

Stop to Think Plot the force vectors upon these two spheres. ( 小心， 力怎麼畫關乎到誰當系統，假定以整個球當作一個系 統好了。 ) 可利用 free-body diagram 與 interaction diagram 來想。 Do this experiment to confirm your thought. Different charge numbers. Different distances

Coulomb’s law ( 請預讀 P800~P804) 14

Using Coulomb’s Law nC (B) +1nC -2nC 5cm nC (B) +1nC -2nC 5cm

Homework Student Workbook

A Problem of Coulomb’s Law and Newton’s Law of Gravity 17 source test t=0 t=t’t=t’

The Field Model ( 請預讀 P805~P810) 18 Newtonian view Faraday’s View: (see animation) A A

The Electric Field 19

Exercises Q1: Plot the electric field created by these two particles. Q2: Which one is the possible electric field? (a)(b)

Homework Student Workbook Student Textbook 自己寫 Terms and Notation. 21