The Drama in Real Cold Stuff: Liquid Nitrogen 
The Drama in Real Cold Stuff: Liquid Nitrogen
by Prof. Miller
Video Lecture 27 of 46
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Date Added: February 5, 2015

Lecture Description

How cold can STUFF get? Theory tells us that the very lowest we can EVER hope to get is -273 C - called Absolute Zero. But who really knows? It might be lower somewhere in this Universe! For ordinary ad¬ventures we can get the following:
Ice and salt -20°C or so.
Dry Ice and alcohol -78.5°C or so.
Liquid Nitrogen -195°C.
And this is pretty cold — as we shall see.

A. A teakettle filled with liquid nitrogen boils on a cake of ice!

B. And now we proceed with a number of things - all showing how
this VERY COLD STUFF changes the properties of ordinary things:
a. We freeze a "hot dog".
b. We freeze an onion.
c. A lead spring which is : lifeless" at room temperatures becomes
d. A rubber ball which bounces at room temperature becomes
frightfully brittle when made so cold.
e. A lead plate which hardly "sings" at room temperature emits a
beautiful high note when very cold. It becomes elastic.
f. A lamp lights so bright - or dim - at room temperature.
We lower the temperature of the coil connected to it. The lamp now flares up. WHY? The electrical resistance of conductors goes down with drop in temperature. . .so the electrical conductivity is higher.

Thus we see that the properties which STUFF possesses changes with the temperature. An understanding of this is very important. The pistons in your automobile engine get very hot. Space vehicles get very cold. On the Moon - with no atmosphere - as we now believe - you could stand at the very edge of light and dark and freeze one side of you and boil the other.

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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