Physical Science · California Grade 7
MS-PS1-2
Analyze and interpret data on the properties of substances before and after the substances interact to determine if a chemical reaction has occurred.
Clarification statement: Examples of reactions could include burning sugar or steel wool, fat reacting with sodium hydroxide, and mixing zinc with hydrogen chloride.
Assessment boundary: Assessment is limited to analysis of the following properties: density, melting point, boiling point, solubility, flammability, and odor.
Chapters
The PE asks students to compare properties before and after substances interact to decide whether a reaction happened. This lesson builds the property toolkit the PE names in its assessment boundary and has students analyze and interpret property data to identify unknowns; the before-and-after comparison itself is the work of Lesson 12, so the role here is practice. Lab 3's vinegar test and the flammability slides give a first look at the before-and-after idea.
Lab 2's decision table, the slide-19 aspirin task, W5 and W6 all put before-and-after property data in front of students and ask them to decide whether a new substance formed and how strong the evidence is. The data stay within the assessment boundary (density, melting point, boiling point, solubility, flammability, odor), with other observations treated as clues that need confirming.
Students must already accept that fizzing, color change and the dark crumbly product of burned steel wool signal new substances before they can ask where the atoms went. The chapter uses those property changes as given evidence and does not re-assess them.
Worksheets (21)
| Chapter | Worksheet | Role | How it connects |
|---|---|---|---|
| Ch. 3 | W1 · The Jar That Sorts Things: Five Liquids, Four Objects Phenomenon exploration | practice | Students begin noticing that a substance has properties, such as density, that do not depend on the size of the sample. That is the kind of property data the PE asks them to analyze; this sheet only starts the habit of observing and questioning. |
| Ch. 3 | W2 · Which Property Is It? Words for Telling Substances Apart Vocabulary in action | practice | Analyzing property data later in the unit depends on knowing which properties (density, melting point, boiling point, solubility, flammability) belong to the substance and which (mass, volume, shape) belong to a particular sample. This sheet builds that language. |
| Ch. 3 | W3 · Sink, Float, Sort: How a Recycling Plant Tells Plastics Apart Reading with evidence | practice | The passage shows density, melting behavior and solubility being used as identifying properties of real substances, the same properties the PE's assessment boundary names. Students practice reading and interpreting property information before they analyze data themselves. |
| Ch. 3 | W4 · Reading the Density Chart and Building an Identification Flowchart Diagrams and models | practice | Students interpret density and melting-point values to identify substances and design the order of tests, which is the data-interpretation practice the PE requires. No chemical reaction is involved yet, so this is practice toward the PE, not evidence of it. |
| Ch. 3 | W5 · Mass, Volume and the Straight Line: Identifying Three Metals from Data Data and graphing | practice | Analyzing density and melting-point data to identify substances is the data-interpretation skill the PE requires, applied here before any interaction between substances. The assessment boundary's properties (density, melting point) are the only ones used. |
| Ch. 3 | W6 · What Is in the Unlabeled Bottle? A Claim-Evidence-Reasoning Case Claim, evidence, reasoning | practice | Students analyze property data against a reference table to identify a substance, using exactly the properties the PE's assessment boundary names. The substances do not interact here, so the task practices the analysis the PE needs rather than assessing the PE itself. |
| Ch. 3 | W7 · Fixing Jamal's Lab Notebook: Six Mistakes About Properties Error analysis | practice | Students who confuse mass with density, dissolving with melting, or sample size with melting point will misread property data later in the unit. Diagnosing those confusions directly builds the interpretation skill the PE requires. |
| Ch. 3 | W8 · Five White Jars: An Evidence Jigsaw Collaborative investigation | practice | Students analyze density, solubility, melting behavior and flammability results against a reference table to identify substances. These are the properties named in the PE's assessment boundary; the task builds the analysis habit before students compare properties before and after a reaction. |
| Ch. 3 | W9 · Design Challenge: A Float-Sink Line for Five Plastics Transfer and design | practice | The whole design rests on interpreting density as an identifying property of each plastic and on recognizing that two substances with nearly equal densities need a different property. No chemical reaction is involved. |
| Ch. 3 | W10 · Substances and Their Properties: Mastery Check Retrieval and mastery check | practice | This check assesses the property-analysis skills the PE depends on (density, melting point, boiling point, solubility, flammability as identifying properties). It does not include substances interacting, so it is evidence of readiness for the PE rather than of the PE itself. |
| Ch. 12 | W1 · The Nail That Changed Color: What Happened in the Blue Jar? Phenomenon exploration | practice | Students observe a change (color, a new coating, a small temperature rise) and are pushed to ask which measured properties, compared before and after, would show whether a new substance formed. This activates the before-and-after reasoning the PE assesses without yet analyzing a dataset. |
| Ch. 12 | W2 · Reactant, Product, Evidence: Sorting the Words of a Reaction Vocabulary in action | supports | The PE asks students to analyze property data before and after substances interact. This sheet builds the vocabulary that makes such an analysis possible: naming the substances before and after, telling an observation from a conclusion, and sorting physical from chemical properties. |
| Ch. 12 | W3 · From Willow Bark to a White Powder: Proving Something New Was Made Reading with evidence | practice | The passage shows why a changed melting point or solubility is evidence that a new substance formed and why one changed property is weaker than several. Students practice the reasoning the PE assesses, using reference values rather than a dataset of their own. |
| Ch. 12 | W4 · Reading the Reaction Map: From Clue to Confirmation Diagrams and models | practice | Students read a before-and-after property comparison for vinegar and baking soda and then construct one for burning magnesium, using density and melting point. This builds the comparison habit the PE assesses but uses supplied reference values rather than data the student analyzes. |
| Ch. 12 | W5 · Three Cups in Numbers: Temperature Clues and the Recovery Test Data and graphing | assesses | Table 2 gives solubility and odor for each starting solid and for the solid recovered afterward, measured at the same temperature. Students compute the differences and decide which cup produced a substance with different characteristic properties, which is the analysis the PE asks for and stays inside its assessment boundary. |
| Ch. 12 | W6 · White Powder In, White Powder Out: Did Heating Make a New Substance? Claim, evidence, reasoning | assesses | Students receive property data for a powder before and after heating, plus two control samples, and must decide in a written argument whether a new substance formed. Solubility, odor and density are inside the PE's assessment boundary; the mass loss and the fogged plate are treated as clues that need the property data to become a claim. |
| Ch. 12 | W7 · Fix the Lab Notebook: Six Conclusions That Went Wrong Error analysis | practice | Each notebook entry pairs an observation (a temperature drop, bubbles, a vanished solid, a shared melting point, a stopped fizz, light) with a conclusion about reaction or no reaction. Students must decide whether the evidence supports the conclusion and what property comparison would, which is the judgment the PE assesses, practiced on short cases rather than on a full dataset. |
| Ch. 12 | W8 · Clue, Proof or Not Yet: The Evidence Sort Collaborative investigation | practice | Every card pairs what was seen with the result of a property test (or notes that none was done). Groups must use the test result, not the clue, to place each card, which builds the before-and-after analysis the PE assesses; the individual section checks that each student can do it alone. |
| Ch. 12 | W9 · Two Creams, One Choice: Confirm the New Substance, Then Judge the Design Transfer and design | practice | Part A puts before-and-after property data in front of students, including three tests that do not separate them, and asks whether the reaction produced a new substance. It transfers the chapter's analysis to a new context inside the PE's assessment boundary. |
| Ch. 12 | W10 · Reaction or Not? Mastery Check Retrieval and mastery check | assesses | The solubility calculation, the melting-point check item, the boiling-versus-fizzing item and the synthesis paragraph each require the student to decide from property data whether a reaction occurred, which is the PE's task inside its assessment boundary. The remaining items retrieve the vocabulary and the conditions ideas that make that analysis possible. |
| Ch. 13 | W1 · Lighter Cup, Heavier Pad: Where Did the Mass Go? Phenomenon exploration | supports | Fizzing and a color change are the evidence that a reaction happened at all. That prior idea from the previous lesson is background here; the new question is what happens to the atoms and the mass. |
Labs (7)
| Chapter | Lab | Role | How it connects |
|---|---|---|---|
| Ch. 3 | Lab 1 · Four Clear Liquids, No Labels Evidence-based mystery | practice | Students collect density and solubility data and interpret it against a reference table, which is the data-analysis practice the PE calls for using two of the properties named in its assessment boundary. No chemical reaction occurs, so the before-and-after half of the PE is left for Lesson 12. |
| Ch. 3 | Lab 2 · Pick the Spoon: Property Data Decides Data-driven decision | practice | Students read and compute with the properties the PE names in its assessment boundary and use them to compare materials, which is the data-interpretation practice the PE requires; no reaction is observed, so the role is practice. |
| Ch. 3 | Lab 3 · Kitchen Solids Survey: Build an Identification Key Classroom field investigation | practice | Students collect and interpret solubility data to identify substances, which is the data-analysis practice of the PE, and the vinegar test asks them to compare what is present before and after two substances interact, which is a small, qualitative version of the PE's before-and-after reasoning. Lesson 12 does the full version, so the role is practice. |
| Ch. 12 | Lab 1 · Mystery Powders: Reactions as Fingerprints Evidence-based mystery | practice | Students record what happens when each powder meets water, vinegar and a baking soda solution, decide which results are reactions and which are dissolving, and use the pattern to identify unknowns. This builds the before-and-after reasoning of the PE without yet asking for a full reaction-or-not judgment on measured properties, which Lab 2 does. |
| Ch. 12 | Lab 2 · Did a Reaction Happen? Six Changes, One Decision Table Data-driven decision | assesses | The decision table requires a property comparison for every change (solubility of the product, recovery of the original substance, a chemical property of the leftover liquid, magnetism and texture of rust) and a reasoned reaction-or-not verdict with an evidence rating. Measured properties stay within the boundary (solubility, odor) or are observational comparisons; density and melting point data are supplied in W5 rather than measured here. |
| Ch. 12 | Lab 3 · When Does the Fizz Stop? A Reaction as a System Collaborative systems modeling | practice | The leftover test compares a chemical property (fizzing with acid, fizzing with baking soda) of the liquid after the reaction with the properties of the reactants, which is the before-and-after reasoning of the PE applied to a reaction the students control. The mass data are the output of the system model rather than a property measurement. |
| Ch. 13 | Lab 1 · Three Balances: Lost, Kept, Gained. Where Did the Grams Go? Evidence-based mystery | supports | Fizzing, the bag inflating and the color change on the pad are taken as given evidence of new substances; students are not re-assessed on identifying a reaction. |