Connected Chemistry Unit 1: Gas Laws
Time: 8 classes, 45-50 min each
Introductory High School Chemistry
This is an 8 day unit designed to cover high-school level topics in the properties of gases and gas particle behavior while engaging students in computational thinking practices. The lessons use computer models to explore these topics in greater depth and using a greater degree of student inquiry and guided discovery than would be typically possible through other learning activities in the same amount of time. Throughout the unit, students will learn the rules that govern gas behaviors and interactions by adding the rules into the model one-by-one. The computer models enable students to investigate what causes pressure in a gas, how it is measured, and how it is affected by the properties of the particles that make the gas and the characteristics of the container they are in (ideal gas law).
In Lesson 1, students first focus on three real-life examples of systems involving gases - a bike tire, a syringe, and a soda can. Then they look at a simple model of the bike tire, observing the particles that make up the gas inside the bike tire. Students explore the model by changing parameters in the interface, gaining a familiarity with a microscopic view of the system and with the NetLogo model interface they will use again in later lessons. Finally, students are introduced to the code behind the model and have an opportunity to modify the code.
In Lesson 2, students are introduced to the scientific concepts of the Kinetic Molecular Theory, pressure, and ideal gases. They are given a definition of pressure and then guided through an investigation of how particles create pressure at the microscopic level. Students observe the effects that adding particles through a valve in the tire has on the pressure of the tire. Students consider the trade-offs of making simplifications when constructing models of systems. They are then introduced to sub-procedures in code and use this tool to to examine what determines the kinetic energy of the simulated particles.
In Lesson 3, students are first introduced to the Command Center - a new tool that is used to examine specific particle properties, change parameters, and learn code. For example, this tools allows the students to track individual particles, control the direction and speed of particles, and color and label the particles. Collisions of individual particles are investigated up close in this lesson, so that students can see how the particle collisions are dependent on the particles’ speeds and directions and conserve kinetic energy. Finally, students use the Command Center to draw with the particles, particularly engaging their creativity in the final challenge.
In Lesson 4, students use a computer model that now includes the effect of warming up and cooling down the bike tire walls. They use this model to examine the relationships between speed of particles and the temperature of the gas as well as between temperature and pressure. Students use the Command Center to collect data and then use a preprogrammed Excel Workbook (or Google Sheet) to find a linear equation of the relationship between temperature and pressure. They use the equation to make predictions about what the pressure will be for temperature conditions.
In Lesson 5, after using Command Center to collect data, students are introduced to a new tool called BehaviorSpace, which automates data collection in the model. They use BehaviorSpace and Excel/Google Sheets to investigate the quantitative relationship between the number of particles in a container and the pressure inside. In Excel/Google Sheets, the students sort and clean their data, then create a graph and find a trendline. Students use the trendline equation to predict and test their prediction for new pressure values.
In Lesson 6, students engage in a hands-on laboratory, placing books on a syringe to demonstrate the relationship between pressure and volume. They then run a BehaviorSpace experiment with a little less guidance than the previous lesson, and analyze the data in more depth using either Excel or Google Sheets. Using both the model and the trendline equation found in their analysis, students examine the particle behaviors that result in the observed relationship between pressure and volume.
In Lesson 7, students connect all their previous gas particle investigations. Accordingly, the model used in this lessons combines the features from previous lessons. Students explore different ways to change parameters and produce the same pressure. They then use the Ideal Gas Law to predict pressure values for different variable combinations and test their predictions using the model. Finally, students return to the code to explore the thought process of constructing this model.
Lastly, in Lesson 8, students are asked to use an open interface in the model to construct representations of a balloon popping and the diffusion of perfume from a bottle. After orientation to this “sketch up” style interface that permits a wide range of ways to draft out new system representations, students are given the opportunity to draw a model of a real world system (or create a model and then argue what real world system it might model). After drawing the model, students can then run the model and gather observations about the behavior of the particles in this system.
- NGSS Crosscutting Concept
- NGSS Practice
- Asking Questions, Defining Problems
- Using Models
- Conducting Investigations
- Analyzing Data
- Arguing from Evidence
Computational Thinking in STEM
- Modeling and Simulation Practices
- Assessing Computational Models
- Designing Computational Models
- Using Computational Models to Find and Test Solutions
- Using Computational Models to Understand a Concept
- Computational Problem Solving Practices
- Assessing Different Approaches/Solutions to a Problem
- Computer Programming
- Troubleshooting and Debugging
- Data Practices
- Analyzing Data
- Collecting Data
- Creating Data
- Manipulating Data
- Visualizing Data
- Systems Thinking Practices
- Investigating a Complex System as a Whole
- Thinking in Levels
- Understanding the Relationships within a System
This work was made possible through generous support from the National Science Foundation (grant 0115699).
Computational Thinking in Science and Math
Lesson 2 Changing Pressure
In this lesson, you will use a scientific model similar to the one you used in the previous lesson. Using this model, you will observe the effects that pumping air into the bike tire has on the tire.