Review

• Discrete Event Simulation
• probabilistic reasoning

Global Heat

• Heat versus Temperature: why can some people walk on coals?
• degrees Kelvin: temperature becomes a ratio quantity
• Concepts:
  1. heat as something that flows around, like phlogiston
  2. means of flow: radiation, conduction, evaporation and convection
  3. albedo
• Heat flows in the model:
  • atmosphere to ground
  • ground to atmosphere
  • atmosphere to space
  • ground to space
• Quantitative models:
  • Rate of some process:

    current_rate = initial_rate * (current_heat/initial_heat)

  • Heat versus temperature. The STELLA model just uses a proportionality and uses:
    • 255K is temp of surface (land and sea)
    • 288K is temp of air
  • Heat Radiation. Bodies in space radiate energy (heat) like:

    F = e s A T⁴

    with a bunch of constants that depend on the type of object

    But we will use the simpler:

    F = H⁴

    where F is the heat flow (in Joules/sec or Watts) and H is the heat.

  Here's our model:

  global-heat.mox

  Falling Rubidium Atoms

  Seila Selimovic ('04) modeled falling cold Rubidium atoms to measure their temperature, based on the following:

  • rate of spread in 2D depends on temperature
  • rate of falling depends on gravity
  • the mode should cross the detector at about the same time
  • the variance should depend on the temperature

  Seila Selimovic's model

  Experiment with this.