- A. General Materials & Mathematics
- B. Statics
- C. Kinematics & Dynamics
- D. Rotational Mechanics
- E. Gravitation & Astronomy
- F. Fluid Mechanics
- G. Vibrations & Mechanical Waves
- H. Sound
- I. Thermodynamics
- J. Electrostatics & Magnetostatics
- K. Electromagnetic Principles
- L. Geometrical Optics
- M. Wave Optics
- N. Spectra & Color
- O. Vision
- P. Modern Physics
I3-33. Helium Balloon On Liquid Nitrogen
To show that helium gas contracts when it is cooled.
Helium balloon, liquid nitrogen.
A helium balloon which is cooled by a liquid nitrogen bath becomes heavier than air. When the balloon is removed from the liquid nitrogen it warms up, expands, and floats away.