Democritus 460-357 BC
Demos to Prepare:
Liquids: Lycopodium Powder is almost a liquid.
Surface Tension and Viscosity.
Ice in Cooking Oil in Cylinder.
Terminal velocity: marbles in Karo Syrup.
1. Gas Pressure. The force of molecular collisions.
A balloon expands as air is added, yet it is still
compressible. Air thermometer.
2. Heat Conduction. From molecule to molecule the
energy is transferred.
3. Evaporation. Moving molecules escaping thru the
surface tension. Warmer evaporates faster.
4. Vapor Pressure. Force of evaporating molecules.
5. Expansion upon heating. Moving and colliding molecules
push each other farther apart. Ball & Ring,
(The Brass Monkey.)
6. Diffusion. The intermingling of moving molecules Coloring in water,
NH3 gas on the loose. 50+50= 95!
7. Osmosis. Diffusion thru a porous membrane.
Graham's Law-- The rate of diffusion is
inversely proportional to the square root
of the molecular mass.
Heavy molecules diffuse more slowly.
8. Brownian Motion. Smoke & dust particles are jostled
around by molecular impact. Keeps clouds up!
9. Electron microscopy photographs!
Viscosity of Cornstarch Video:
Our guys test this idea, video:
Momentum vs Tensile Strength. Can a cable attached to the rear axle of a cop car rip off the axle? Video:
Surface Tension Video:
Demos of the Kinetic Theory:
Gas Model Video:
If a gas molecule were as large as a bee, and the container as large as a duck, we could see the impact of molecular collisions on the walls of the container, Video:
Graham's Law Video:
Brownian Motion Video:
Electron Microscope photos show atoms and that they are in motion.
Finding Absolute Zero, video:
Much Molecular Motion takes place with Alkalai Metals in Water. Video:
Here Endeth The Kinetic Theory