Miscellaneous Adventures in Heat 
Miscellaneous Adventures in Heat
by Prof. Miller
Video Lecture 26 of 46
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Date Added: February 5, 2015

Lecture Description

The subject is filled with DRAMA. NATURE is wonderful to contemplate.

A. We do an old classic - boil water in a tin can - stopper it up -
and the atmosphere does its stuff! Incredible really. I suppose I
have done this very adventure ten thousand times and it never fails
to stir me. What do we do? We condense the water vapour in the
can - the pressure is reduced - the atmosphere pushes the can in.
And - if we listen carefully we can hear the water boiling in the
can. Now try to pull out the stopper; it is fixed in very firmly.

B. We lodge a silver coin in a block of dry ice - solid CO2. And a
wonderful thing ensues. The coin oscillates and sings. Why? The
heat energy in the coin "melts" some of the dry ice. Gas arises.
This pushes the coin over to one side. Conduction is better on
closer contact and gas arises on this side. Silver is a good conductor. Moreover - the pitch of the note emitted gets higher as
the coin gets colder. Watch for this. We shall see more of this in
the demonstrations on sound as well as in the next adventures on
REALLY COLD STUFF.

C. For the housewife: To cook hamburgers fast cook 'em slowly! Why?
When cooked FAST they are likely to be burned on the outside. Carbon is a good thermal insulator. So the meat is burned on the outside but not cooked on the inside! Thus PHYSICS plays an important
role in the kitchen!

D. Does peeling onions make you cry? Solution: Chill them. The vapour pressure is lowered and they do not trouble you so much. Again
PHYSICS.

E. VISCOSITY: how easily - how readily - how swiftly - do things
FLOW? We have heard the phrase: As slow as cold molasses. So
the viscosity of liquids goes DOWN with rise in temperature. Just
what the oil in the crankcase of your car does. And so when you
pour cold molasses the "glubs" are slow and sluggish. When warm
they are faster.

F. A strange thing indeed! A very carefully designed copper sphere
- hollow - has a very special volume and a very special weight.
It has some lead or copper "shot" inside it to give it EXACTLY the
weight we wish. We put this sphere in a beaker of warm water.
IT SINKS. Add ice - cool the water - the sphere comes UP. OR - start again. Put this sphere in a beaker of COLD water. It floats. As time goes by the water warms up - as we say. And now the sphere sinks. WHY IS THIS? The density of water varies with its temperature.

G. We have discovered that the viscosity of liquids goes DOWN with
rise in temperature. How about the viscosity of gasses? Or gases?
Strangely enough the viscosity of gases goes UP with rise in temperature. And we show this with an un-symmetric T-tube. When the
matter is more fully explored and we know enough mathematics we
can prove all these things by Kinetic Theory arguments or by Quantum Mechanics.

As a closing adventure we play with the silver coin on the dry ice once again. This device has its historical origins in a mechanism called THE TREVELYAN ROCKER - which you might look up.

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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