Teaching Lesson 3

The most important concept here is that to examine the chemical reaction and discover that there is a missing product from the model. It is important to understand that the model is a very simple representation of the real reaction. Running more experiments using the model shows how much easier and more time efficient and cost-effective it is to run a model of the reaction rather than perform it in real life and to do it over and over again.


Review the activities from Lesson 3 as well as the material below. Reflect on how you would teach this in your class. Post your reflection to your portfolio in "Pedagogy->Module 4" under the heading Lesson 3.

Lesson Objectives

The student will:

- Identify the products of a chemical reaction [LO11]

- Identify the factors that stop a chemical reaction [LO12]

- Learn about concepts of limiting reactants and reactants in excess [LO13]

- Learn the importance of balancing chemical equations [LO14]

- Learn how to make new breeds and create agents in agent-based modeling [LO15]

Teaching Summary

Getting started – 5 minutes

1.     When does a chemical reaction stop?


Activity #1:  Modifying the model – 25 minutes

2.     The production of copper nitrate


Activity #2: Running experiments – 15 minutes

3.     Different initial quantities of copper or silver nitrate


Wrap-up – 5 minutes

4.     What are models good for?

Assessment questions (suggested):

      What were the reactants in the chemical reaction we studied?

      What were the products in the chemical reaction we studied?

      What determines which are the limiting reactants? 

      What determines which are the reactants in excess?

      In your own words, describe the law of conservation of mass.

NRC Scientific and Engineering Practice Standards

Practice 1: Asking questions and defining problems

1A: Ask questions that arise from careful observation of phenomena, models, or unexpected results.

1B: Ask question to identify and/or clarify evidence and/or the premise(s) of an argument.

1C: Ask questions to determine relationships between independent and dependent variables and relationships in models.

1D: Ask questions to clarify and/or refine a model, an explanation, or an engineering problem.

1E: Ask questions that require sufficient and appropriate empirical evidence to answer.

1F: Ask questions that can be investigated within the scope of the classroom, outdoor environment, and based on observations and scientific principles.

1G: Ask questions that challenge the premise(s) of an argument or the interpretation of a data set.


Practice 2: Developing and using models

2A: Evaluate limitations of a model for a proposed object or tool.

2B: Develop or modify a model—based on evidence – to match what happens if a variable or component of a system is changed.

2C: Use and/or develop a model of simple systems with uncertain and less predictable factors.

2D: Develop and/or revise a model to show the relationships among variables, including those that are not observable but predict observable phenomena.

2E: Develop and/or use a model to predict and/or describe phenomena.

2G: Develop and/or use a model to generate data to test ideas about phenomena in natural or designed systems, including those representing inputs and outputs, and those at unobservable scales.


Practice 4: Analyzing and interpreting data

4D: Analyze and interpret data to provide evidence for phenomena.

4G: Analyze and interpret data to determine similarities and differences in findings.


Practice 5: Using mathematics and computational thinking

5C: Create algorithms (a series of ordered steps) to solve a problem.


Practice 6: Constructing explanations and designing solutions

6A: Construct an explanation that includes qualitative or quantitative relationships between variables that predict(s) and/or describe(s) phenomena.

6B: Construct an explanation using models or representations.

6D: Apply scientific ideas, principles, and/or evidence to construct, revise and/or use an explanation for real-world phenomena, examples, or events.

6E: Apply scientific reasoning to show why the data or evidence is adequate for the explanation or conclusion.

6H: Optimize performance of a design by prioritizing criteria, making tradeoffs, testing, revising, and re-testing.


Practice 8: Obtaining, evaluating, and communicating information

8E: Communicate scientific and/or technical information (e.g. about a proposed object, tool, process, system) in writing and/or through oral presentations.

NRC Disciplinary Core Ideas

PS1.A: Structure and Properties of Matter

   Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.

   Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it.

   Gases and liquids are made of molecules or inert atoms that are moving about relative to each other.

   In a liquid, the molecules are constantly in contact with others; in a gas, they are widely spaced except when they happen to collide. In a solid, atoms are closely spaced and may vibrate in position but do not change relative locations.

   Solids may be formed from molecules, or they may be extended structures with repeating subunits (e.g., crystals).

PS1.B: Chemical Reactions

   Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.

   The total number of each type of atom is conserved, and thus the mass does not change.

   Some chemical reactions release energy, others store energy.

NRC Crosscutting Concepts

1. Patterns:

1A: Macroscopic patterns are related to the nature of microscopic and atomic-level structure.


3. Scale, Proportion, and Quantity

3A: Time, space, and energy phenomena can be observed at various scales using models to study systems that are too large or too small.

3C: Proportional relationships (e.g., speed as the ratio of distance traveled to time taken) among different types of quantities provide information about the magnitude of properties and processes.

3E: Phenomena that can be observed at one scale may not be observable at another scale.


4. Systems and Systems models

4B: Models can be used to represent systems and their interactions—such as inputs, processes and outputs—and energy, matter, and information flows within systems.

4C: Models are limited in that they only represent certain aspects of the system under study.


5. Energy and Matter:

5A: Matter is conserved because atoms are conserved in physical and chemical processes.


6. Structure and Function

6A: Complex and microscopic structures and systems can be visualized, modeled, and used to describe how their function depends on the shapes, composition, and relationships among its parts; therefore, complex natural and designed structures/systems can be analyzed to determine how they function.


7. Stability and Change:

7A: Explanations of stability and change in natural or designed systems can be constructed by examining the changes over time and forces at different scales, including the atomic scale.



CSTA K-12 Computer Science Standards




Discuss the value of abstraction to manage problem complexity.


Data representation


Use visual representation of problem state, structure and data.


Modeling & simulation


Evaluate the kinds of problems that can be solved using modeling and simulation.


Modeling & simulation


Interact with content-specific models and simulations to support learning and research.


Data collection & analysis


Collect and analyze data that are output from multiple runs of a computer program.




Implement a problem solution in a programming environment using looping behavior, conditional statements, logic, expressions, variables and functions.