Lesson 3 Activity 1 - Modify the model

In this lesson students will engage in discussion on the reactants and products of a chemical reaction. Emphasis is on balancing chemical equations, the amounts of reactants used up and products formed. Focus will be on the products and the observation of the atomic rationale for conservation of mass.
  • Watch the video that describes the challenge, to add a missing product
  • Learn New CS Concepts and Commands
    • how to add breeds
  • Modify the model to add a missing product, copper nitrate
  • Test you model

Watch a video introduction to the challenge

New CS concepts and commands:
Breeds are subclasses of agents:
Introduce the concept of inheritance wherein all agents inherit from the “everyone” breed in StarLogo Nova. This means that a procedure specified in the everyone page can be used by all agents.  Then show how the Wiggle procedure can be moved into the “everyone” page and removed from the other breed specific pages. Why might this be a good idea? [Avoids duplication, prevents one of the breeds from having a different behavior, and is easy to change, since it is in one place.]


Use the Edit Breeds button in the Spaceland area to create a new breed.

Click on “Add Breed” to add a new breed.

In the “New Breed” dialog box, give the breed a name and press OK.

Modify the model

Your challenge is to modify the model by adding the production of copper nitrate.

Review the chemical reaction being represented in the base model so far and what is missing. Aqueous silver nitrate added to solid copper will react to form solid silver and aqueous copper nitrate.

In a balanced chemical equation format:

2 AgNO3 (aq) + Cu (s) ---> Cu(NO3)2 (aq) + 2 Ag (s)

Note that in our model we have breeds for AgNO3 , Cu, and Ag, but no Cu(NO3)2. We are missing one of the products!  The concept of conservation of mass states  that all mass must be accounted for. So for our model to be more accurate, we must account for all of the products. 

Test and Debug:

  • After adding your breed and creating it, test your setup. Did your Copper Nitrate agents appear? Are they the color, shape and size you wanted them to be?
  • Test your agent's behaviors.  Are they moving in solution as you expected?


Upload a link to your model and a reflection on adding a new breed to your portfolio in the section "SL Nova Projects-Physical " under the heading "Adding Copper Nitrate".

Optional Extension: (if time allows)
  • Move this whole collision procedure from the copper page to the silver nitrate page. Change the heading of the collision block to reflect “On collision with copper” instead of “On collision with silver nitrate” and execute the model. What do you notice? [The silver ends up deposited at the location of the center of the silver nitrate rather than the copper. As a result, the copper strip does not get “plated” evenly.]