Sounding Pipes 
Sounding Pipes
by Prof. Miller
Video Lecture 34 of 46
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Date Added: February 5, 2015

Lecture Description

A - We have a wind-chest - an air-tight box so equipped at the top that we can place pipes in holes so they can be blown simultaneously. We start with two identical pipes - identical length - identical diameter - and therefore identical pitch. We sound them together. They emit alike. Now the question: How can we change the pitch of a pipe? Answer: By various means. First we change its length with a sliding sleeve. Doing this gives rise to beats with the other pipe. The greater the difference in lengths the greater the beat frequency. If one pipe has a frequency f. and another a frequency f„ -the beat frequency will be f„ - f,. And now else can we change the pitch? By changing the medium with which the pipe sings. So we heat one pipe and beats again rise. The higher the temperature of the air in the pipe the higher the velocity of sound in the pipe and the higher the pitch.

B - We show the amazing performance of thermally-excited pipes. A metal pipe has a bit of metal screen lodged in it. We heat the screen. Re¬move the pipe from the heat source. And an enchanting thing is witnessed. The pipe sings! With the pipe held horizontally no convection can exist so no music can come out. As I like to say: The music cannot fall out when the pipe is horizontal! And further exploration of this sort-reveals what we expect: Longer pipes have lower pitch. AND - note well this detail: These metal pipes with wire screen sing AFTER they are removed from the heat source.

C - We now explore the enchanting behavior of CARDBOARD TUBES - the like of which rugs come rolled on. This I call intellectual fun! These pipes can sing while they are being energized! A whole array of these could provide a Bach choral! Are we not agreed that SINGING PIPES have enchantment abundant?

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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