Electrostatic Phenomena: Foundations of Electricity 
Electrostatic Phenomena: Foundations of Electricity
by Prof. Miller
Video Lecture 37 of 46
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Date Added: February 5, 2015

Lecture Description

All stuff is electric in nature! Everything is electric! Stones - stars -all living things. For all stuff is made up of atoms - and atoms are made up of charged particles.

A - It was THALES in ancient Greece who first reported the strange behavior wherein amber when rubbed acquired the property of attracting unto itself light bits of straw and dust. THIS was the foundation of all electrical science. So we show these things with a rubber rod rubbed with fur. Cork dust is quickly ''attracted".. AND - quite as important - the dust is soon DRIVEN AWAY. It is very important to UNDERSTAND these actions. Coulomb forces are strong and ever-present.

B - We show similar effects with a pocket-comb We do work by rubbing the comb on something. Charges are separated. Electric energy is thus made available.

C - We define the charge on a rubber rod when it is rubbed with fur as NEGATIVE. The fur therefore has an equal measure of POSITIVE charge. Similarly - a glass rod rubbed with silk has on it - by definition - a POSITIVE charge. To determine the nature of an unknown charge we use an ELECTROSCOPE which we can charge by CONDUCTION or by INDUCTION. The sequence of operations in both is very important. When an electroscope is charged by CONduction the charge on the instrument is that of the charger. When an electroscope is charged by INduction the charge on it is opposite that of the inducer.

D - Pith balls hang on silk strings. They are first electrically or electrostatically NEUTRAL. We now approach them with a charged rod. They flee swiftly to the rod - touch it - hang on a moment - and soon swiftly swing away_ They first FEEL the effects of induction. Then on contact they are charged by conduction. Having now the same charge as the rod they flee from the rod and from each other.

E - And where will an electroscope be unaffected by an electric field?
Answer: in a closed metal conductor - as in a wire cage. And thus we learn what places are safe in a lightning storm.

F - To show how ENORMOUS these electrostatic forces CAN be: Place a long 2 by 4 or a heavy clean plank astride a watch-glass so it can turn freely. Stroke one end of the 2 by 4 swiftly with a cat's fur. Also charge a rubber rod with fur. Now approach the end of the log with the charged rod. It turns! The electrostatic forces are really massive. It is an interesting exercise to compare these electric forces with the gravitational forces.

Finally this must be said: Although the operations we have done in this Lesson seem trivial they are fundamental to the science of ELECTRICITY and indeed constitute the FOUNDATIONS of all electrical science.

Course Index

  1. The Idea of the Center of Gravity
  2. Newton's First Law of Motion: Inertia
  3. Newton's Second Law of Motion: The Elevator Problem
  4. Newton's Third Law of Motion: Momentum
  5. Energy and Momentum
  6. Concerning Falling Bodies & Projectiles
  7. The Simple Pendulum and Other Oscillating Things
  8. Adventures with Bernoulli: Bernoulli's Principle
  9. Soap Bubbles and Soap Films
  10. Atmospheric Pressure
  11. Centrifugal Force and Other Strange Matters
  12. The Strange Behavior of Rolling Things
  13. Archimedes' Principle
  14. Pascal's Principle: The Properties of Liquids
  15. Levers, Inclines Planes, Geared-wheels and Other Machines
  16. The Ideas of Heat and Temperature
  17. Thermometric Properties and Processes
  18. How to Produce Heat Energy
  19. Thermal Expansion of Stuff: Solids
  20. Thermal Expansion of Stuff: Gases & Liquids
  21. The Strange Thermal Behavior of Ice and Water
  22. Heat Energy Transfer by Conduction
  23. Heat Energy Transfer by Convection
  24. Heat Energy Transfer by Radiation
  25. Evaporation, Boiling, Freezing: A Dramatic Adventure
  26. Miscellaneous Adventures in Heat
  27. The Drama in Real Cold Stuff: Liquid Nitrogen
  28. The Physics of Toys: Mechanical
  29. The Physics of Toys: Acoustic and Thermal
  30. Waves: Kinds of Properties
  31. Sound Waves: Sources of Sound & Pitch and Frequency
  32. Vibrating Bars and Strings: The Phenomenon of Beats
  33. Resonance: Forced Vibrations
  34. Sounding Pipes
  35. Vibrating Rods and Plates
  36. Miscellaneous Adventures in Sound
  37. Electrostatic Phenomena: Foundations of Electricity
  38. Electrostatic Toys, Part 1
  39. Electrostatic Toys, Part 2
  40. Adventures with Electric Charges
  41. Adventures in Magnetism
  42. Ways to "Produce" Electricity
  43. Properties and Effects of Electric Currents
  44. Adventures in Electromagnetism
  45. Further Adventures in Electromagnetism
  46. Miscellaneous and Wondrous Things in E&M

Course Description

Demonstrations in Physics was an educational science series produced in Australia by ABC Television in 1969. The series was hosted by American scientist Julius Sumner Miller, who demonstrated experiments involving various disciplines in the world of physics. The series was also released in the United States under the title Science Demonstrations.

This program was a series of 45 shows (approximately 15 minutes each) on various topics in physics, organized into 3 units: Mechanics; Heat and Temperature / Toys; and Waves and Sound / Electricity and Magnetism.

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