Description of Chapters

The PSET course consists of six chapters of activities. The course is hierarchical, with both topics and skills developed in a structured progression around some powerful common themes.

1: Interactions and Energy

The first chapter introduces students to all of the common themes of the course. The concept of interactions is first introduced in the context of "contact push/pull interactions" between rigid objects that are touching and pushing or pulling on each other. Students investigate both interactions that involve involve friction (when the objects' surfaces rub one another) and do not involve friction.

Students use motion sensors and graphing software to investigate the motion of objects in these interactions, and then use a computer simulator to determine the effect of removing friction completely. From their results, they infer that the effect of such interactions is to change the motion of an object in some way.

In parallel, they are also introduced to an energy description for interactions that can be easily represented in diagrammatic form.

In the fourth activity, students investigate two interactions between objects of different temperatures: heat conduction interactions, which occur when objects in contact with one another have different temperatures; and infrared interactions, which occur between objects of different temperature that may or may not be in contact. In this context, students are introduced to the idea of objects engaging in heat conduction or infrared interactions with the surrounding environment, particularly when an interaction involving friction has caused objects to become warmer than their surroundings. In this way, students develop the idea that heat conduction and infrared interactions are pervasive. 

The fifth activity investigates the connection between light and seeing by examining how light reflects off shiny and non-shiny surfaces, and whether or not light needs to enter the eye for seeing to occur. They develop an energy description of the light interaction. The homework that follows this activity examines elementary students' ideas about the relationship between light and seeing, and how those ideas evolve after the children engage in experiments similar to those the PSET students performed in the preceding activity. 

The sixth activity introduces the electric circuit interaction as students investigate the conditions necessary to light a single bulb. Like the other interactions introduced in this chapter, students develop an energy description of the electric circuit interaction (including a homework that examines the connection between bulb wattage and rate of energy transfer to the bulb). This foundation of energy descriptions of interactions prepares them to follow the energy: to keep track of energy inputs to systems, energy outputs, and changes in system energy in various simulator set-ups in the seventh activity. From this investigation, students construct an energy conservation rule applicable to both open and closed systems:

Energy Input = Energy Output + Energy Changes within the System

After they have developed their ideas, students are introduced to a procedure that they use to construct and evaluate energy-based explanations of various phenomena. 

2: Interactions and Forces

This chapter introduces students to an alternative framework (that of forces) within which they can explain the same contact push/pull interactions they first saw in Chapter 1. Chapter 2 is written to explicitly address common misconceptions many students hold about the nature of forces and their connection to the motion of an object.

Students again use motion sensors and computer simulators to gather evidence on the effect that a single force has when it is applied to a cart under various conditions. From this evidence they construct a set of ideas that is equivalent to Newton’s first two laws of motion. The ideas are extended to combinations of forces in a homework assignment. These ideas are then applied in constructing force-based explanations for phenomena.

In this chapter students are also introduced to the ideas of elementary students about forces, with two Learning about Learning homework assignments.

3: Interactions and Fields

The first activity in this chapter uses the context of the interactions between two magnets, and between magnets and ferromagnetic metals, to allow students to consider interactions that involves ‘action at a distance’. In the context of energy conservation, students are also introduced to the idea of potential energy, and the idea that this energy is contained within the system of interacting objects itself, rather than any specific object.  A homework assignment lets students choose which of two competing models of magnetism better explains magnetic phenomena. A second LAL assignment examines how historical models of magnetism explain or don't explain observed phenomena.

In the second activity, students consider the 'action at a distance' and potential energy ideas in the context of the electric charge interaction. In the next activity, students consider the gravitational interaction using both energy and force frameworks. They examine the interplay between stored energy and motion energy. In the final application activity, students explain 'action at a distance' phenomena using both energy and force ideas. In the concluding LAL homework, they then consider the relationship between observations and models.

Chapter 4: Interactions and the Behavior of Gases

This chapter introduces the scientists' Small Particle Model (SPM) of matter and applies it to phenomena involving gases, making extensive use of computer simulators that model the behavior of gases on both macroscopic and microscopic scales. They use the simulators to examine the connection between macroscopic mass and volume, and microscopic number density. 

The first activity introduces the SPM of gases. In the second activity, students use the SPM and the simulator to investigate gas pressure, and in a homework they use ideas they are developing to explain phenomena involving pressure. In the third activity, students use the the simulator to investigate the relationships between temperature and other parameters, including volume, pressure and particle speed and energy. In a homework, students use the relationships between different parameters to develop the Ideal Gas Law, and then in the last activity use the ideas they have developed to explain phenomena involving gases.

This chapter includes three LAL homework assignments. In the first assignment, they examine children's ideas about gases and compare them to their own ideas. The second assignment examines the utility of the small particle simulators as models. At the end of the chapter, students complete a special homework assignment in which they examine the nature of science in the context of the process they have gone through in PSET to develop their own ideas and models. 

5: Interactions and Physical Changes

Chapter 5 focuses on physical properties and changes in the context of liquids and solids. Students begin with an activity that introduces them to the idea of density as a characteristic property of a material, followed by a homework in which they investigate the role of density in sinking and floating. In the second activity, students use small experiments and SPM simulators to investigate particle movement and spacing in solids and liquids, and then for homework they use simulators to develop a description of density for matter in all three phases (solid, liquid, gas). In the third activity, students use experiments and simulators to learn about how heating liquids and solids changes them, and about the connection between temperature, particle motion and spacing. Following this activity is a LAL homework in which students examine children's ideas about density, sinking and floating and compare them to their own. 

Students spend the next two activities studying changes of phase. They first examine melting and boiling of water in the context of the small particle model using both a hands-on experiment and SPM simulators, followed by a homework assignment in which they use simulators examine the melting and boiling of materials other than water to discover what determines melting and boiling temperatures. Then they examine evaporation and vapor pressure of water and methanol in the context of the small particle model.

The sixth activity examines solubility. In hands-on experiments, students compare the solubility of different substances in hexane and water; determine whether sugar, salt or baking soda has the highest solubility; and how temperature affects the solubility of a solid (baking soda) and a gas (carbon dioxide). Finally, they develop a simple model for solubility at the particle level. In the homework, they use ideas about density and solubility to examine "real-world" phenomena. In the final activity, students explain phenomena using the ideas developed in this chapter, and in the final homework 


6: Interactions and Chemical Changes

Chapter 6 focuses on chemical changes and their particle-level underpinnings, employing both in-class experiments and simulators that model chemical reactions and decomposition on both the macroscopic and microscopic scales. In the first activity, students perform a variety of experiments to gather evidence (new substances forming) for chemical changes, and then find that chemical changes cannot be reversed through physical changes. For homework, students examine the relationship between the rate of chemical change and temperature. 

In the second activity, students investigate the decomposition of lead iodide and find evidence that heating can lead to a chemical change. They also learn the idea of atoms and molecules as the smallest units of materials, learn the difference between elements and compounds, and develop a small-particle conception of a chemical change. In a homework assignment, they investigate models of the atom. The third activity introduces students to the Periodic Table of Elements, and they learn about the relationship between element properties and the organization of the table. The fourth activity extends that lesson by relating atomic structure to element properties and the periodic table. In a homework assignment, students examine different types of molecular bonds. 

Students are introduced to chemical equations in the fifth activity, and they use the chemical simulators to balance chemical equations. From these activities, they learn about the connection between balanced chemical equations and conservation of mass.  In the final (seventh) activity, students use the ideas they have developed to write explanations for phenomena involving chemical changes. 

During this chapter, students also complete a ‘learning about learning’ assignment that allows them to reflect on the learning process itself and their own personal learning during the course. This assignment is followed by the last LAL activity (the sixth of Chapter 6), in which students review social scientists' ideas about learning science and decide to whom they apply: themselves, children, and/or scientists. This leads to a discussion about the learning process during one of the final class periods.