Classroom Demos
These classroom demonstrations were designed by Prof. John Hart at the University of Colorado Boulder. Construction of the experiments and filming of the clips on this website was carried out by Scott Kittelman and John Hart. Some of the equipment used in the demonstrations was obtained from previously-completed externally-funded research projects within the GFD Lab. We are grateful to the National Science Foundation, Physical Meteorology and Physical Oceanography Programs, and the National Aeronautics and Space Administration, Microgravity Sciences Program, for support of this effort.
1. Adiabatic” Expansion: Paul Bunyan’s Bicycle Pump.
2. Atmospheric Electricity: Van de Graf generator shows inductive charging, breakdown, how a lightning rod works….
3. Atmospheric Optics: 1/r^2 Simple beam area demonstration.
4. Atmospheric Optics: Orientation of falling ice crystals. Drop tube shows how hexagons and needles fall.
5. Baroclinic Waves: The rotating annulus experiment (Hadley motion, baroclinic instabilty, vacillations, etc.)
6. Buoyancy: neutral: hand-around demonstration of neutrally buoyancy particles.
7. Buoyancy: Lava lamp illustrates differential thermal expansion.
8. Chaos I: Periodically forced pendulum shows periodic, multiply periodic, chaotic states.
9. Chaos II: Orbits of ODE’s. Laser projector driven by ODE solver shows trajectories from various nonlinear ODE’s . (A wall-sized oscilloscope.)
10. Cloud chamber demonstrates need for nuclei, fog formation and dissipation.
11. Coriolis Effect: Air hockey on a rotating planet
12. Coriolis Effect: Particle motion on a rotating platform. Also shows inertial circles.
13. Doppler Effect
14. Drinking Ducks: Vapor pressure, evaporation, volatility.
15. Ekman Layers: Horizontal convergence under a cyclone, divergence out under an anticyclone.
16. Ekman Layers: Spin up and spin down in various containers (timescales, symmetry breaking….).
17. Expansion of Air: Handboiler illustrates various properties of gases and liquids (expansion, boiling, volatility..)
18. Gravity Currents: Simple two-fluid cell illustrates gravity currents. Compare speed to theory.
19. Hadley Cell: Convection from a horizontally localized heat source.
20. Heat Transport: Convection, radiation, conduction. Use with thermocouple or IR camera.
21. Hydrostatics: Hero’s fountain shows a paradox explained by simple hydrostatics.
22. Ice Crystal Orientation While Falling. Use drop tube to illustrate flat-fall of model plates.
23. Inertial Oscillations: Particle motion on a rotating parabola shows inertial circle oscillations.
24. Instability of a Two-Fluid Interface: Illustrate Kelvin-Helmoltz instability.
25. Instability of a Two-Fluid Interface: Illustrate Rayleigh-Taylor instability.
26. Instability of Hadley Circulations: The rotating annulus experiment. (Hadley motion, baroclinic instabilty, vacillations, etc.)
27. Instability of Rotating Flow: Instability and transition in Taylor-Couette flow.
28. Instability of Stratified Shear Flows: Tilt tank shows instability, wave breaking, etc..
29. Internal Gravity Waves: Illustrate phase and group velocity. Resonance.
30. IR Absorption and Emissivity: Measuring IR from and through various materials.
31. IR Imaging: 3 micron video camera sees what class is drinking (hot, cold, etc.), illustrates IR emissivity of water vapor.
32. Latent Heat and Boiling: Monitor T(t) during boiling. Estimate energy required to boil off a certain mass of water.
33. Latent Heat:Exothermic re-heaters demonstrate latent heat release, nucleation, supercooled liquids.
34. Momentum Conservation: Ninja balls show dramatic consequences of multiple elastic collisions.
35. Mountain Airflow: Water channel illustrates flow over mountain, shocks and bores, lee waves.
36. Ocean Circulations:Demonstrate western intensification – independent of sign of forcing (cyclonic or anticyclonic).
37. Pressure, Power of: Collapsing cans, and the Mt. Evans Barrel.
38. Rainbows: 2-Color laserlight ray tracing – Color separation and beam focusing.
39. Refraction: The Green Flash – Green edge of sun, red edge of sun.
40. Rotating Annulus: Demonstrate Hadley motion, baroclinic instability, vacillation, etc.
41. Rotating Fluids:Taylor Proudman effect: Flow around topography in a rapidly rotating fluid.
42. Saturation Vapor Pressure: P(saturated air) and P(dry air) vs. T.
43. Scattering: Reddening by small particle scattering.
44. Sea Breeze: Convection from a horizontally localized heat source.
45. Shock Waves: Water channel illustrates flow over mountain, shocks and bores, lee waves.
46. Spin Up: Spin up and spin down in varous containers (characteristic timescales, symmetry breaking, etc.).
47. Sprites and Jets: Discharge tube illustrates dependence of ionization on pressure.
48. Supercooled Liquids: Exothermic re-heaters need trigger to undergo liquid => solid phase change.
49. Taylor-Couette Flow: Instability and transition.
50. Taylor Proudman Effect: Flow avoids topography in a rapidly rotating fluid.
51. Terminal Velocity: Drop tube with viscous fluid illustrates dependence of terminal velocity on size.
52. Thermal Convection I: Simple demonstration of planforms and wavelength selection in evaporation driven convection (Marangoni or combined surface-tension/buoyancy).
53. Thermal Convection II: Simple convection cell shows planforms on projection screen.
54. Thermal Convection III: Convection of viscous fluid in a frying pan shows patterns and wavelength selection.
55. Vortex Generator – Large: Illustrate cyclostrophic balance…
56. Vortices in a Bottle.
57. Vorticity Mechanics: Simple tools to illustrate stretching and tilting.
58. Waves – Internal Gravity: Illustrate phase and group velocity. Resonance.
59. Waves – Capillary-Gravity: Laterally forced capillary-gravity waves in a closed basin. Show dispersion relation, non-linear pattern selection, spatio-temporal chaos.
60. Waves: Mechanical demonstration of transverse waves. Restoration due to tension.
61. Waves – Nonlinear: Water channel illustrates flow over mountain, shocks and bores, lee waves.
Note: Some demonstration write ups include movie clips. Some of these are in two versions: a relatively short QuickTime movie with a small area on the screen, and a QuickTime “Big Screen” version that is much larger on the screen (typically 720 x 480 pixels), but which takes much longer to download. The file size for “Big Screens” is 3 – 20 MegaBytes, while the regular movies are generally less than a MegaByte. The Big Screen version is provided for possible stand-alone use by itself as a class video.