SUCCEED

5 minutes

What is a Scientific Model?

• Representation of a natural occurrence utilizing prior knowledge

Examples of scientific models (ask for ideas):

• Weather models
• Virtual Product testing (car crashes etc)
• Environmental models (wildfire spread, etc)
• Traffic Models

What can we use a scientific model for?

• Testing Hypotheses
• Analysis of Scenarios
• Drawing Conclusions to certain problems
• Investigating happennings that are difficult to observe in real life

Agent Modeling

• Individual behaviors -> Emergent properties
• "Agents" have particular behavior
• The resulting system has observable properties.

15 minutes

Open Rabbit-Grass-Weeds Model

Introduce students to NetLogo interface

• Tabs: Interface, Information, Procedure
• Buttons: ("forever" versus "one-time")
• Sliders: Initial and dynamic values
• Switches
• Monitors
• Plots

Elements of the model

• Turtles = agents
• Patches = background (actually a kind of agent that can't move...)

Run the model and make observations

• Individual behaviors?
  • Eat grass
  • Reproduce
  • Move
  • Die (as a result of starving)
• Emergent properties?
  • More grass -> More rabbits
  • More rabbits -> Less grass
  • Less grass -> Less rabbits
  • Less rabbits -> More grass
  • It's a cycle! (Point out graph)
• What does it mean?
  • Predator / Prey (or herbivore / vegetation) levels fluctuate in a cycle (could show hare/lynx graph online)
• What factors produce more rabbits?
  • Lower Birth Threshold (more fluctuation)
  • Higher Grass Energy
  • Higher Grass-Grow-Rate

Make changes to the model

• What happens when we hit the "setup" button?
• Go to the procedures tab and find "to setup"
  • Each procedure is a set of instructions telling the computer how to do something
• Introduce commenting - it's like turning code off (putting ;; before a line of code to turn it off, or putting it at the end of the line to still execute the command but also put in a note about the code)
• Comment out or change different lines of code and observe changes (do only one comment at a time)
  • set color white (change color)
  • setxy random-xcor random-ycor (random positions)
  • set-default-shape of the rabbits to "cow" (change shape)
  • Tools->Shapes Editor for shape names

30 minutes

Introduce a color changing model (5 min)

• When two turtles meet, one of them will become the color of the other. Eventually, all the turtles will be the same color. This represents the spread of a fad or, in a more scientific approach, genetic traits leading to evolution.
• What will a turtle have to do?
  • Be created
  • Move
  • Change colors
  • Know if another turtle is nearby, and how to respond
• Write the steps in your notebook
• Write kids' ideas on the board

Build the model we worked on (20 min)

• What procedures do we need?
• Write these steps as comments first, then fill in the commands.
  • setup
    • Clear all
    • Create 100 turtles
    • Position turtles (remember what happened in the rabbit model?)
• go
  • Move turtles
  • Change turtle color
• move
  • Rotate turtles
  • Move forward one step
• Change-color
  • Any turtles around me?
  • Set my color to the color of one of my neighbors

Could have a longer class or a second class where the students build on their original model and add more behaviors.

Diffused background:

ask patches [

set pcolor sky + random 30 - 14

]

diffuse pcolor 1

If there are no student computers, the class can make observations and give input to sample models that the teacher displays on the projector.

Other interesting models to explore:

• Wolves and Sheep
• Flocking