Conservation of Mass

breed [reactantAs reactantA] ; this is a synthesis reaction with two reactants and one product
breed [reactantBs reactantB]
breed [products product]

to setup
  clear-all ; clear.
  set-default-shape reactantAs "circle" ; set shapes for the three turtles.
  set-default-shape reactantBs "circle"
  set-default-shape products "circle molecule"
  
  create-reactantAs amount-of-reactantA ; slider reactantA sets number of green reactantA turtles, placed randomly.
    [set color green
      set size 1
      setxy random-xcor random-ycor]
  create-reactantBs amount-of-reactantB ; slider reactantB sets number of blue reactantB turtles, placed randomly.
    [set color blue
      set size 1
      setxy random-xcor random-ycor]
  reset-ticks ; resets ticks.
end 

to go ; begins reactant behavior.
  ask turtles 
    [right random-float 15 - random-float 15 fd 1] ; turtles move randomly.
    if count reactantAs = 0 [show "reaction complete!" stop] 
    ; checks if reactantA is gone, gives message to observer, and stops reaction.
    if count reactantBs = 0 [show "reaction complete!" stop] 
    ; checks if reactantB is gone, gives message to observer, and stops reaction.
  react ; calls sub-routine react.
  tick ; adds one tick.
end 

to react ; sub-routine which allows the reactants to create a product.
  ask one-of reactantAs ; asks one of the reactantAs to determine if it shares a space with a reactantB.
    [if any? reactantBs in-radius 1
    [set breed products ; if reactantA and reactantB share the same space, reactantA becomes the product with size 2.
      set size 2
     ask one-of reactantBs in-radius 1 [die]]]; at the same time as reactantA becomes the product, reactantB dies.
end 

; kellyryanscience@gmail.com