• Recognize that the model of matter that we use during this unit is essentially that proposed by Democritus.
  • Relate observations of diffusion to particle motion and collision in both liquid and gas phases.
  • Relate observations regarding the addition of energy by warming to increased particle motion.
  • Explain, at the particle level, how a thermometer measures the temperature of the system.
  • Explain the basis for the Celsius temperature scale.
  • State the basic tenets of Kinetic Molecular Theory (KMT) as they relate to gases. Particles of a gas:
    • are in constant motion, moving in straight lines until they collide with another particle or a wall of the container in which they are enclosed.
    • experience elastic collisions; i.e., they do not eventually “run down”
    • do not stick to other particles.
  • The speed of the particles is related to their temperature.
  • The pressure of a gas is related to the frequency and impact of the collisions of the gas particles with the sides of the container in which they are enclosed.
  • The 3 variables P, V and T are interrelated. Any factor that affects the number of collisions has an effect on the pressure. You should be able to:
    • Predict the effect of changing P, V or T on any of the other variables.
    • Explain (in terms of the collisions of particles) why the change has the effect you predicted.
    • Explain the basis for the Kelvin scale. Keep in mind that one must use the absolute temperature scale to solve gas problems.
    • Use factors to calculate the new P, V or T. Make a decision as to how the change affects the variable you are looking for.




Structure of the Atom 1: The Earliest Models

Ring of Truth

Eureka Videos:

  1. Particles in  Solid
  2. Particles in a Liquid
  3. Evaporation & Condensation
  4. Expansion & Contraction
  5. Measuring Temperature
  6. Temperature vs. Heat

The 1st Celsius Thermometer
The World’s Longest Straw
Pressure Conversions
Crush the Can Demo
Boyle’s Law
Charles’ Law
Gay-Lussac’s Law
Combined Gas Laws Practice Problems (2.7)
Ideal Gas Laws
Dalton’s Law (partial Pressure)
Phase Change Diagrams
Vapor Pressure


Gizmo: Phase Changes
Boyle’s Law and Charles’s Law
pHet: Exploring Gas Properties 
C-K12 Phase Diagrams
NetLogo Diffusion Simulator


Pressure Concept Builder
Diffusion Activity