Unit 3 — Changes to Matter
Description
Students investigate how objects made of small pieces can be disassembled and recombined into new objects, observing that matter can be broken into smaller pieces and reassembled. They conduct experiments with heating and cooling to discover reversible changes such as melting butter or freezing water, and irreversible changes such as cooking eggs or burning paper. Students construct arguments with evidence distinguishing between reversible and irreversible changes, using their observations to support claims about cause-and-effect relationships between heat and matter.
Essential Questions
- How can objects change?
- Are all changes reversible?
- What happens when we heat or cool materials?
Learning Objectives
- Make observations to construct evidence-based accounts of disassembling and reassembling objects
- Construct arguments with evidence that some heating and cooling changes are reversible and some are not
- Observe patterns in events generated by cause-and-effect relationships
- Use evidence from investigations to support thinking about reversible and irreversible changes
Supplemental Resources
- Lined journals for sketching and recording observations of matter changes
- Paper for creating before-and-after comparison drawings
- Markers and colored pencils for illustrating reversible and irreversible changes
- Graphic organizers for sorting change types
- Index cards for labeling examples of reversible and irreversible changes
Physical Sciences
Students participate in shared research and writing projects using trade books and digital resources to support science learning across all units. They ask and answer questions about key details in informational texts, describe connections between scientific ideas and concepts, recall and gather information from provided sources to answer questions, write opinion pieces with evidence to support claims, create audio recordings and add visual displays to clarify ideas, and recount key ideas from texts read aloud or presented through media. These literacy practices are explicitly referenced in connection with standards 2-PS1-1 through 2-PS1-4, 2-LS2-1, 2-LS2-2, 2-LS4-1, 2-ESS1-1, 2-ESS2-1, 2-ESS2-2, 2-ESS2-3, K-2-ETS1-1, K-2-ETS1-2, and K-2-ETS1-3.
Students apply mathematical practices and content standards throughout the science units. They reason abstractly and quantitatively, model with mathematics, and use appropriate tools strategically when collecting and analyzing data from investigations. Students draw picture graphs and bar graphs with single-unit scale to represent data sets with up to four categories, read and write numbers to 1000 using base-ten numerals and expanded form, and use addition and subtraction within 100 to solve word problems involving lengths. These mathematical connections are explicitly referenced in relation to standards 2-PS1-1, 2-PS1-2, 2-LS2-1, 2-LS2-2, 2-LS4-1, 2-ESS1-1, 2-ESS2-1, 2-ESS2-2, K-2-ETS1-1, and K-2-ETS1-3.
Formative Assessments
- Observations recorded when building and deconstructing objects with small pieces
- Drawings showing before and after states of materials when heated or cooled
- Written or oral explanations distinguishing reversible from irreversible changes
- Data from heating and cooling experiments documenting observable changes
Summative Assessment
Students identify physical properties of matter and determine whether specific changes caused by heating or cooling are reversible or irreversible.
Benchmark Assessment
Break objects into smaller pieces and reassemble into larger pieces or change shapes.
Alternative Assessment
Students may demonstrate understanding through a verbal explanation to an adult of whether a heating or cooling change is reversible or irreversible, with visual aids such as photographs or actual material samples used to support their response. Drawings or manipulatives may be used in place of written labels or descriptions.
IEP (Individualized Education Program)
During hands-on investigations with heating, cooling, and object assembly, provide visual supports such as before-and-after picture sequences to help students process and record what they observe. Allow students to demonstrate understanding of reversible and irreversible changes through oral explanation, labeled drawings, or dictation rather than requiring extended written responses. Break multi-step experiments into clearly numbered stages with simplified language, and offer sentence frames to scaffold evidence-based arguments about cause and effect.
Section 504
Provide preferential seating during demonstrations involving heating and cooling materials to ensure clear sightlines and reduce distraction. Allow extended time for recording observations and completing before-and-after drawings, and offer a printed copy of any directions given verbally or on the board so students can reference steps independently throughout investigations.
ELL / MLL
Build vocabulary for this unit—such as 'reversible,' 'irreversible,' 'melt,' 'freeze,' and 'matter'—using illustrated word walls, picture-supported vocabulary cards, and real objects or demonstrations before the concept is introduced in instruction. Provide simplified, visual directions for experiments, and allow students to discuss their observations in their home language with a partner before sharing with the class or recording their thinking.
At Risk (RTI)
Connect new concepts to familiar, everyday experiences with heating and cooling—such as ice melting on a warm day or bread toasting—to activate prior knowledge and give students a concrete entry point into abstract ideas like reversibility. Reduce the complexity of recording tasks by offering partially completed observation charts or drawings with labeled prompts, focusing mastery on the core distinction between changes that can and cannot be undone rather than the full breadth of content.
Gifted & Talented
Challenge students to investigate the boundary conditions of reversible and irreversible changes by generating their own questions about what factors—such as the amount of heat or the type of material—might influence whether a change can be undone. Encourage students to move beyond describing observations toward constructing more sophisticated cause-and-effect arguments, considering how changes at the observable level might connect to the idea that matter is made of smaller pieces that can be rearranged or permanently altered.