3/16 Model ideas and standard

For class I have been looking at the strong acid titration model in NetLogo. The model itself is useful to show kids how to plot a titration curve on a graph. The model also shows how the pH of a reaction needs time to balance out, as the ions are reacting with one another. I planned on making a few changes to the model. First, the model offers in the info section to add an ‘add acid’ button. This will be helpful to students who accidentally add too much base too quickly to the reaction and need to reattempt making a curve without starting the model over. Next, I planned on making the model specific as to what indicator will be used in the titration. The most common (and by that I mean the one I have used the most) is phenolphthalein. Phenolphthalein turns pink in the presence of hydronium ions. In other words, during a titration when using phenolphthalein as an indicator, the solution turns pink for moments when base is added to the solution and hydronium ions of phenolphthalein are released. When the solution becomes neutral, the solution remains colorless.

Here’s a link to what it looks like: https://www.youtube.com/watch?v=8UiuE7Xx5l8

I wanted to add this effect to the NetLogo model. However, I’ve been having trouble figuring out how to write this code into the model. I looked at the dictionary but can’t seem to get the code to work. Lastly, wondering about a ‘what if’ question to add to the model, I wanted to add a molarity slider for the base of the solution. With this added effect, students will be able to see the difference in titrations that are using a base with possible as low as 0.001 M solution possibly up to 10.0 M solution. Students could then compare the titration graphs of the different solutions and be able to predict the concentration of an unknown solution.

This could be included in the NGSS: HS-PS1-6. Refine the design of a chemical system by specifying a change in conditions that would produce increased amounts of products at equilibrium. Students investigating the beginning levels of reactants, how much reactant is added during the reaction, changing the molarity of the reactants and predicting the molarity of an unknown reactant are all covered in this standard.

What are your thoughts about my ideas for the model? And do you have any suggestions?

I need help writing the code for the model so anyone with ideas or who has possibly done something similar concerning changing the patches of the model that could help would be appreciated!