Thermal Expansion of Stuff: Gases & Liquids 
Thermal Expansion of Stuff: Gases & Liquids
by Prof. Miller
Video Lecture 20 of 46
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Date Added: February 5, 2015

Lecture Description

Some strange and uncommon things occur in these adventures. For example: how can a gas which is HOT feel COLD? Let's look at some of these unusual things.

A. Here is an ordinary automobile tire - inflated. We agree that
the atmosphere is hot - the ground is hot - the tire is hot -
the air in the tire is hot. Now we depress the valve stem and out
comes some HOT air. But how does it feel? IT FEELS COLD!
IT IS COLD! That is - its temperature is lower the instant it
emerges.
B. There is a simpler demonstration of this strange business: The air
in my lungs is HOT. I now blow out some of this air from my
mouth. With my mouth wide open the air coming out IS HOT.
With my lips pursed as if to blow a whistle the air comes out
COLD! So - I am a strange creature: I can blow both hot and
cold!

C. Consider a CO2 fire extinguisher. We release the gas. The temperature drops so low that we get "CO2 snow".

D. We have a device which might well be called a SPUTNIK! It is
like a Hero's engine. A CO2 cartridge is lodged in a chamber -
the cartridge is pricked - the gas emerges - the Laws of Newton
play their proper role and the arm rotates. The gas comes out this—
a-way — the chamber goes that-a-way! Our interest here is this:
it is so cold that the water vapor in the room has condensed on it
and there is "frost" on the cartridge.

E. A cast-iron "bomb" is filled with water. ... filled completely with
the occluded gases first gotten rid of. We place this vessel in a
tub - a pail - of ice water. The water IN the chamber freezes.
The forces of expansion are tremendous and the "bomb" is shattered.
Dangerous to do! And we encounter this strange property of water:
that it expands when it freezes.

The forces arising in the expansion of a gas can be nicely shown with an Earth-bound Rocket. A steel pipe is tightly closed at one end. The pipe is filled with solid CO2 - "dry ice". The open end of the chamber is stoppered up. The CO2 goes into gas. The pressure increases. Out pops the stopper.

G. The Galilean Thermometer is an enchanting historical piece. A glass vessel of spherical shape has a one-hole stopper fitted to it with a glass tube. The vessel is held in a clamp upside down with the open end of the glass tube in a beaker of colored water. The air in the spherical vessel is cooled - say with ice put on it. The liquid in the lower beaker "climbs" up into the spherical chamber. If now with the column of liquid high in the tube the spherical vessel is warmed - as by placing the hand on it - the liquid is driven down. Here is an example of a higher column - a longer column - meaning a LOWER temperature! Nor must we forget the role that pressure plays in this demonstration. Galileo's thermo-meter was really a pressure-meter!

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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