Generation Science Standards (NGSS) that specify concepts and activities into smaller,
measurable pieces. The first step of this analysis involved determining which of the Disciplinary Core Ideas (DCIs) standards and science practices (SPs) from the NGSS were best aligned with the POM simulation. Table 8 shows the final DCIs and SPs that were chosen for this simulation. The two DCIs identified cover the primary content standards of the simulation: changes in matter and energy during phase change. The DCI standard PS1.A describes the changes that occur during phase change to the density and movement of the molecules. The other DCI standard
(PS3.A) includes a description of the relationship between changes in energy and the phases of matter. As this standard encompasses multiple aspects of the standard, such as those related to energy in physics, it is important that the PEs specify the relevant concepts.
Table 8
Disciplinary Core Ideas and Science Practices for the POM Simulation
NGSS Dimension Code Excerpt(s) of descriptions from standards
Disciplinary Core Ideas
PS1.A Structure and Properties of Matter: 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 each other; in a gas they are widely spaced except when they happen to collide. In a solid, atoms are closely spaced and vibrate in position but do not change relative locations. The changes of state that occur with variations in temperature (or pressure) can be described or predicted using this model of matter.
PS3.A Definitions of Energy: The term “heat” refers...to thermal energy (the motion of atoms or molecules within a
substance) ... In science...it refers to energy transferred when two objects or systems are at a different temperature...The relationship between the temperature and the total energy of a system depends on the types, states, and amounts of matter present.
Science Practices
SP.2 Developing and Using Models: Develop and/or use a model to predict and/or describe phenomena.
SP.4 Analyzing and Interpreting Data: Analyze and interpret data to data to provide evidence for phenomena.
SP.7 Engaging in Arguments from Evidence: Construct, use and present...written arguments supported by empirical evidence and scientific reasoning to support or refute an explanation or a model for a phenomenon
Determining the SPs that were most aligned to the POM simulation was more
challenging than the DCIs because there were multiple SPs that could be applied depending on the goals of the simulation. The “Developing and Using Models” practice (SP.2) was a clear
match to the POM simulation because simulations are considered models and students needed to use the simulation to complete the task. There were three other SPs that could be applicable to the POM simulation: “Engaging in Arguments from Evidence” (SP.7), “Planning and Carrying out Investigations” (SP.3), and “Analyzing and Interpreting Data” (SP.4). Although simulations do offer environments that are supportive for conducting experiments, SP.3 was not chosen as a standard because the POM simulation did not have a way of identifying whether students were explicitly testing hypotheses. Future iterations of this simulation could make the hypotheses and trials more explicit in the data collection if this SP is a goal. Ultimately, SP.4 was chosen
because it encompasses the practices students would need to use for the table and reflection. In order to complete the table, students would need to interpret the data from the graphs in the simulation, as well as data form the visualization. The practice SP.7 was also chosen for this simulation because the structure of the fill-in-the blank options for the reflection and open-ended questions allow students to make an argument, identify evidence, and use it to apply the
information to the macro context.
From the identified standards, the next step in this phase of analysis was to identify PEs, by combining the relevant aspects of the DCIs and SPs into expectations situated in the POM simulation. The DCIs and SPs can be applied to a wide range of contexts, so it is necessary for the PEs to specify the exact content and activities the students will engage in while using the simulation (see Table 9). The three PEs align with the three different activities students need to engage with in order to complete the POM simulation: manipulate variables in the simulation to explore the phenomena, complete the table, and answer the reflection questions. While each of the SPs have their own PE, the DCIs cut across the PEs and both DCIs appear in two of the PEs. This reflects the coverage of the content across the whole simulation.
Table 9
Performance Expectations for the POM Simulation
PE Associated DCIs and SPs Description of PE
PE.POM.A DCI: PS1.A SP: SP.2
Students can use a model (simulation) to observe changes in particle motion,
temperature, and status of a substance when thermal energy is added or removed.
PE.POM.B DCI: PS1.A, PS3.A SP: SP.4
Students can analyze and interpret data from the simulation about the effect of changes in
thermal energy on molecular movement,
intermolecular bonds, and the amount of kinetic energy.
PE.POM.C DCI: PS1.A, PS3.A SP: SP.7
Students can construct and use written
arguments, supported by empirical evidence and scientific reasoning, to support their
explanations about the role of changes in energy and molecular movement on macroscopic matter changes
The next step in Phase II of the analysis was to create the LPs for each PE (see Table 10). Although a single LP does not cover all aspects of a PE, the LPs taken together are designed to cover the different facets of the PE. The goal of the LPs was to make concrete statements about what students should do and know with respect to the POM simulation. The LPs LP.POM.A.1-3 relate to PE.POM.A and provide the critical actions students would do if they were manipulating the simulation in the manner in which the simulation was designed. Specifically, students should observe all three states of matter in order to understand the molecular differences in terms of speed and density (LP.POM.A.1). Students should also observe all of the transitions between states in order to understand that phase changes are gradual and observe the melting and boiling points where the phase change is initiated (LP.POM.A.2). In order to accomplish the first two LPs, students should use the simulation in effective and efficient ways (i.e., pausing the
different aspects of the simulation, and following direct navigation paths through the simulation) (LP.POM.A.3). The first two LPs specify the specific actions that students would need to
complete in order to view all parts of the simulation necessary to fill in the table and answer the reflection question. The third LP for this PE is more related to how the students used the
simulation and whether their pattern of actions follows a more expert path. Table 10
Learner Performances for the POM Simulation Performance
Expectation
Learner Performance
Description of Learner Performance
PE.POM.A LP.POM.A.1 Students observe all three states of matter that are
required to complete the simulation
LP.POM.A.2 Students add or remove thermal energy in the simulation
to observe critical transitions between all three states of matter
LP.POM.A.3 Students productively use the simulation maximize
learning potential (i.e., viewing more than once, efficient learning patterns)
PE.POM.B LP.POM.B.1 Students collect correct, descriptive data from the
molecular representation, including the density and speed of molecules at different states
LP.POM.B.2 Students collect and correctly interpret data from graphs
LP.POM.B.3 Students make correct interpretations about the changes
in matter and energy between states of matter
PE.POM.C LP.POM.C.1 Students can identify and articulate correct concepts
about energy and matter during phase change
LP.POM.C.2 Students can use identified evidence and scientific
reasoning to support their explanations about the role of changes energy and matter on the macroscopic
phenomena of a balloon inflating over boiling water LP.POM.B.1-3 relate to PE.POM.B and focus on how students would collect and interpret data from the simulation to fill out the table. The first LP for this PE (LP.POM.B.1) captures student work to fill-in the table cells related to molecular speed and density that they
would have gotten from the molecular visualization. The second LP (LP.POM.B.2) covers the work students would need to do to accurately interpret the graphs about kinetic energy and intermolecular bonds. The third LP (LP.POM.B.3) refers to whether students are able to make and describe correct inferences about the relationships between the states in terms of matter and energy. Although this LP was not directly called for in the task, more accurately describing energy and matter in the table involves specifying the relationships between states because students are collecting observations and qualitative data, rather than quantitative measurements that may be found in other experiments.
Finally, LP.POM.C.1-2 relate to PE.POM.C and describe what students would need to do to correctly answer the reflection questions. LP.POM.C.1 relates to whether students can identify correct concepts related to the simulation. The last LP (LP.POM.C.2) looks at whether students can use argumentation practices by identifying evidence to support claims about the relationship between micro- and macroscopic concepts related to the balloon expanding, as well as
supporting the claim with evidence.
Summary of Phase I results. The first phase of analysis resulted in a list of LPs derived
from performance expectations aligned with specific standards from the NGSS. The process of identifying standards and creating subsequent PEs and LPs, adapted from methods proposed by McElhaney et al. (2017), is an important step in the evidence centered design process because it helps define the student model. The disciplinary core ideas and science practices by themselves are not specific enough and do not account for the intersection of the two dimensions, making the specification of more fine-grained expectations necessary. The final list of eight LPs
encompass the expected performance of students in terms of both their conceptual understanding and use of the POM simulation.
Phase II results: Defining and applying evidence rules. The second phase of analysis