Science Task Screener

Task Title: Conservation of Mass: The Unbroken Chain of Atoms

Grade: High School

Date: 2024-05-20

Instructions

• Before you begin: Complete the task as a student would. Then, consider any support materials provided to teachers or students, such as contextual information about the task and answer keys/scoring guidance.
• Using the Task Screener: Use this tool to evaluate tasks designed for three-dimensional standards. For each criterion, record your evidence for the presence or absence of the associated indicators. After you have decided to what degree the indicators are present within the task, revisit the purpose of your task and decide whether the evidence supports using it.

Criterion A. Tasks are driven by high-quality scenarios that are grounded in phenomena or problems.

i. Making sense of a phenomenon or addressing a problem is necessary to accomplish the task.

What was in the task, where was it, and why is this evidence?

1. Is a phenomenon and/or problem present?

Yes. The task opens with a concrete, everyday phenomenon: a log burning in a campfire, leaving only a small pile of ash. The driving question “where does the rest of the mass go?” is presented in the Engage section and used to anchor all subsequent investigation.

1. Is information from the scenario necessary to respond successfully to the task?

Yes. Students must engage with the simulation to collect data (balanced equations, atom inventories, mass readouts, balance scale results) in order to answer the phenomenon question. The CER synthesis in Part 5 explicitly requires connecting simulation data back to the burning-wood phenomenon. A student cannot answer the task without the scenario context and simulation data.

ii. The task scenario is engaging, relevant, and accessible to a wide range of students.

Features of engaging, relevant, and accessible tasks:

Suggestions for improvement of the task for Criterion A:

None. The phenomenon is concrete, relatable, and effectively motivates the need for mathematical modeling.

Criterion B. Tasks require sense-making using the three dimensions.

i. Completing the task requires students to use reasoning to sense-make about phenomena or problems.

Consider in what ways the task requires students to use reasoning to engage in sense-making and/or problem solving.

Students must reason from collected data (atom counts, mass values) to the claim that mass is conserved. For the burning-wood phenomenon, they must reason that the missing mass was not destroyed but rather released as invisible gases (CO₂, H₂O vapor, etc.) — analogous to what the simulation shows for methane combustion. This requires inductive reasoning from three separate reaction systems to a general principle. The CER structure in Part 5 explicitly scaffolds this reasoning process.

ii. The task requires students to demonstrate grade-appropriate dimensions:

Evidence of SEPs (which element[s], and how does the task require students to demonstrate this element in use?)

Using Mathematics and Computational Thinking — Students must balance chemical equations (finding correct coefficients), compute total mass of reactants and products using atomic masses (H=1, C=12, O=16, N=14), record atom inventories, and compare numerical mass values to verify conservation. The simulation provides real-time computational feedback (mass readouts, balance scale) that students must interpret mathematically. Data tables require precise numerical recording.

Evidence of CCCs (which element[s], and how does the task require students to demonstrate this element in use?)

Energy and Matter — Students track matter as it transforms from reactants to products in three reactions. The CCC element “Matter is conserved because atoms are conserved in physical and chemical processes” is directly assessed. Students must trace atoms across the reaction and account for all matter, including invisible gaseous products. The connection between the visible solid (ash) and the invisible gases (CO₂, H₂O) embodies the matter-tracking aspect of this CCC.

Evidence of DCIs (which element[s], and how does the task require students to demonstrate this element in use?)

PS1.B Chemical Reactions — The core idea that “the total number of each type of atom is conserved, and thus the mass does not change” is the central concept. Students demonstrate understanding by balancing equations (showing atom conservation), computing masses (showing mass conservation), and applying the principle to explain a real-world combustion reaction. All three simulation reactions (water synthesis, methane combustion, ammonia synthesis) exemplify PS1.B.

iii. The task requires students to integrate multiple dimensions in service of sense-making and/or problem-solving.

Consider in what ways the task requires students to use multiple dimensions together.

Students use mathematical calculations (SEP) to track the movement of atoms (CCC: Energy and Matter) through chemical reactions (DCI: PS1.B). For example, when balancing methane combustion, a student must apply coefficients mathematically (SEP) to ensure each atom type is conserved (DCI) while tracking that carbon atoms end up in CO₂ and hydrogen atoms in H₂O (CCC). The CER synthesis requires all three dimensions: the claim draws on the DCI, evidence comes from mathematical modeling (SEP), and reasoning connects atom tracking (CCC) to the phenomenon.

iv. The task requires students to make their thinking visible.

Consider in what ways the task explicitly prompts students to make their thinking visible (surfaces current understanding, abilities, gaps, problematic ideas).

Students make their thinking visible through multiple mechanisms: (1) generating “need to know” questions in the Engage phase, (2) recording data in structured tables during Explore, (3) writing analytical responses to sensemaking questions in the Explain phase, and (4) composing a full CER argument in the Elaborate/Evaluate phase. The CER structure in particular requires students to articulate their claim, cite specific evidence, and explain the reasoning chain — making their full understanding (or misconceptions) visible.

Suggestions for improvement of the task for Criterion B:

None. The three dimensions are well-integrated throughout the 5E structure.

Criterion C. Tasks are fair and equitable.

i. The task provides ways for students to make connections of local, global, or universal relevance.

Consider specific features of the task that enable students to make local, global, or universal connections to the phenomenon/problem and task at hand. Note: This criterion emphasizes ways for students to find meaning in the task; this does not mean “interest.” Consider whether the task is a meaningful, valuable endeavor that has real-world relevance–that some stakeholder group locally, globally, or universally would be invested in.

Combustion is a universal experience — campfires, car engines, gas stoves, forest fires, power plants. Understanding that mass is conserved and that combustion produces gases (CO₂ contributing to climate change) connects directly to global environmental issues. The ammonia synthesis reaction connects to fertilizer production and global food supply, while water synthesis is fundamental to understanding chemical change itself.

ii. The task includes multiple modes for students to respond to the task.

Describe what modes (written, oral, video, simulation, direct observation, peer discussion, etc.) are expected/possible.

Simulation interaction (clicking, adjusting coefficients, running reactions), written responses (questions, data tables, CER argument), and mathematical computation (mass calculations). The simulation provides visual, interactive, and numerical modalities. Teachers could also incorporate peer discussion and oral presentation of CER arguments as extensions.

iii. The task is accessible, appropriate, and cognitively demanding for all learners (including English learners or students working below/above grade level).

iv. The task cultivates students’ interest in and confidence with science and engineering.

Consider how the task cultivates students interest in and confidence with science and engineering, including opportunities for students to reflect their own ideas as a meaningful part of the task; make decisions about how to approach a task; engage in peer/self-reflection; and engage with tasks that matter to students.

The task empowers students to “discover” conservation of mass through their own data collection rather than being told the principle. Generating their own “need to know” questions gives ownership of the inquiry. The CER format validates students’ own reasoning. The campfire scenario is immediately relatable, building confidence that science can explain everyday experiences.

v. The task focuses on performances for which students’ learning experiences have prepared them (opportunity to learn considerations).

Consider the ways in which provided information about students’ prior learning (e.g., instructional materials, storylines, assumed instructional experiences) enables or prevents students’ engagement with the task and educator interpretation of student responses.

Assumes basic prior knowledge: (1) understanding that atoms exist and are the building blocks of matter, (2) familiarity with chemical formulas (e.g., H₂O, CO₂), (3) basic arithmetic skills for calculating mass from atom counts. No prior experience with balancing equations is required — the simulation guides that process. These are reasonable expectations for high school students in a chemistry or physical science course.

vi. The task presents information that is scientifically accurate.

Describe evidence of scientific inaccuracies explicitly or implicitly promoted by the task.

No inaccuracies. The reactions presented (2H₂ + O₂ → 2H₂O; CH₄ + 2O₂ → CO₂ + 2H₂O; N₂ + 3H₂ → 2NH₃) are correctly balanced. The atomic masses used (H=1, C=12, N=14, O=16) are standard approximate values. The simulation’s balance scale, atom inventory, and mass readout accurately reflect conservation principles.

Suggestions for improvement of the task for Criterion C:

None.

Criterion D. Tasks support their intended targets and purpose.

Before you begin:

1. Describe what is being assessed. Include any targets provided, such as dimensions, elements, or PEs:

A high-quality 3D assessment of HS-PS1-7: Use mathematical representations to support the claim that atoms, and therefore mass, are conserved during a chemical reaction. The task specifically targets the evidence statement components: (1) representation — students represent quantities of reactants and products in atoms and mass; (2) mathematical modeling — students use mole concepts and atomic masses to convert between atom counts and mass; (3) analysis — students describe how their representations support the claim of conservation.

1. What is the purpose of the assessment? (check all that apply)
   • Formative (including peer and self-reflection)
   • Summative
   • Determining whether students learned what they just experienced
   • Determining whether students can apply what they have learned to a similar but new context
   • Determining whether students can generalize their learning to a different context
   • Other (please specify):

i. The task assesses what it is intended to assess and supports the purpose for which it is intended.

Consider the following:

1. Is the assessment target necessary to successfully complete the task?

Yes. Students must use mathematical representations (balanced equations, mass calculations) to support the claim that mass is conserved. Without demonstrating this mathematical reasoning, students cannot complete the CER synthesis or answer the sensemaking questions.

1. Are any ideas, practices, or experiences not targeted by the assessment necessary to respond to the task? Consider the impact this has on students’ ability to complete the task and interpretation of student responses.

No. The task does not require knowledge of reaction mechanisms, kinetics, thermodynamics, or any content beyond basic atomic theory and arithmetic. The simulation handles coefficient balancing interactively, so students focus on the mathematical reasoning rather than procedural equation-balancing skill.

1. Do the student responses elicited support the purpose of the task (e.g., if a task is intended to help teachers determine if students understand the distinction between cause and correlation, does the task support this inference)?

Yes. The CER synthesis specifically asks for a claim about mass conservation, evidence from the simulation (balanced equations, mass values), and reasoning that connects the evidence to the claim. This directly supports the teacher’s ability to determine whether students understand that atoms are conserved (and therefore mass is conserved) during chemical reactions.

ii. The task elicits artifacts from students as direct, observable evidence of how well students can use the targeted dimensions together to make sense of phenomena and design solutions to problems.

Consider what student artifacts are produced and how these provide students the opportunity to make visible their 1) sense-making processes, 2) thinking across all three dimensions, and 3) ability to use multiple dimensions together [note: these artifacts should connect back to the evidence described for Criterion B].

Three artifacts are produced: (1) a completed data table with balanced equations and mass values (visible evidence of SEP: Using Mathematics and Computational Thinking), (2) written responses to analytical questions in the Explain phase (visible evidence of reasoning with DCI and CCC), and (3) a full CER argument (visible evidence of integrated 3D thinking). The CER in particular forces students to articulate how mathematical evidence (SEP) supports the claim of atom/mass conservation (DCI) and connects to the tracking of matter (CCC).

iii. Supporting materials include clear answer keys, rubrics, and/or scoring guidelines that are connected to the three-dimensional target. They provide the necessary and sufficient guidance for interpreting student responses relative to the purpose of the assessment, all targeted dimensions, and the three-dimensional target.

Consider how well the materials support teachers and students in making sense of student responses and planning for follow up (grading, instructional moves), consistent with the purpose of and targets for the assessment. Consider in what ways rubrics include:

1. Guidance for interpreting student thinking using an integrated approach, considering all three dimensions together as well as calling out specific supports for individual dimensions, if appropriate:

An answer key provides balanced equations (2H₂ + O₂ → 2H₂O, CH₄ + 2O₂ → CO₂ + 2H₂O, N₂ + 3H₂ → 2NH₃) with expected mass values: water synthesis (4g H₂ + 32g O₂ = 36g H₂O), methane combustion (16g CH₄ + 64g O₂ = 44g CO₂ + 36g H₂O), and ammonia synthesis (28g N₂ + 6g H₂ = 34g NH₃). A rubric for the CER evaluates claim clarity, evidence specificity (citing exact mass values), and reasoning quality (connecting atom conservation to mass conservation).

1. Support for interpreting a range of student responses, including those that might reflect partial scientific understanding or mask/misrepresent students’ actual science understanding (e.g., because of language barriers, lack of prompting or disconnect between the intent and student interpretation of the task, variety in communication approaches):

The data table provides a low-language-demand entry point; students who struggle with written expression can still demonstrate understanding through correct numerical values. The scaffolded CER structure (Claim-Evidence-Reasoning) helps separate different facets of student understanding. Partial credit is available for correct data collection even if the written reasoning is incomplete.

1. Ways to connect student responses to prior experiences and future planned instruction by teachers and participation by students:

The task serves well at the start of a stoichiometry unit to establish the conservation principle, or as a culminating assessment after instruction on balancing equations and mole concepts. The CER responses help teachers identify which students need additional support with mathematical reasoning versus conceptual understanding of conservation.

iv. The task’s prompts and directions provide sufficient guidance for the teacher to administer it effectively and for the students to complete it successfully while maintaining high levels of students’ analytical thinking as appropriate.

Consider any confusing prompts or directions, and evidence for too much or too little scaffolding/supports for students (relative to the target of the assessment—e.g., a task is intended to elicit student understanding of a DCI, but their response is so heavily scripted that it prevents students from actually showing their ability to apply the DCI).

Directions are clear and sequential. The 5E structure provides an appropriate level of scaffolding without overdirecting. The data table template guides recording without prescribing the answers. The CER prompt tells students what to include (claim, evidence, reasoning, specific data sources) without providing the content. This balance supports analytical thinking while ensuring all students understand what is expected.

Suggestions for improvement of the task for Criterion D:

None.

Overall Summary

Consider the task purpose and the evidence you gathered for each criterion. Carefully consider the purpose and intended use of the task, your evidence, reasoning, and ratings to make a summary recommendation about using this task. While general guidance is provided below, it is important to remember that the intended use of the task plays a big role in determining whether the task is worth students’ and teachers’ time.

This is a complete, high-quality, and equitable NGSS task that directly targets HS-PS1-7. The 5E structure effectively scaffolds student learning from anchoring phenomenon through data collection and sensemaking to a culminating CER argument. The three simulation reactions provide sufficient data variety to support robust mathematical modeling. All four criteria earn an “Adequate” rating with no substantive deficiencies identified. The task integrates the three dimensions throughout and supports both formative and summative assessment purposes.

Final recommendation (choose one):

• Use this task (all criteria had at least an “adequate” rating)
• Modify and use this task
• Do not use this task