This project equips my 8th grade physical science classroom with measurement instruments — digital scales, overflow cans, density block sets, and salinity refractometers — to support a phenomenon-based unit in which students investigate why mangrove propagules float, disperse, and establish themselves in Southwest Florida's brackish estuaries. Students will collect real water samples, measure density and salinity directly, and use that data to construct evidence-based explanations (CER) for a phenomenon that exists in their own ecosystem. In short, this project ensures students have the tools they need to connect their classroom density instruction to our local coastal environment guaranteeing an opportunity to make abstract physical science concepts concrete and personal.
This project directly supports the following standards:
• SC.8.P.8.3 — Explore and describe the densities of various materials through measurement of their masses and volumes
• SC.8.P.8.4 — Classify and compare substances based on characteristic physical properties (density, solubility, and others), understanding that these properties are independent of sample size
• SC.8.P.8.9: Distinguish among mixtures (including solutions) and pure substances.
Students will move beyond calculating density from given numbers measuring mass and volume, testing displacement, comparing salinity across water samples, and using that evidence to explain a real environmental phenomenon (propagule float/orientation) through the Claim-Evidence-Reasoning framework central to CCPS’s instructional model.
This project supports Collier County Public Schools' emphasis on hands-on, standards-aligned STEM instruction and phenomenon-based learning, and reflects the district's broader push toward authentic, place-based science that connects classroom content to our local environment.
a) How will students actively participate?
Students will work in small groups (3–4 students) rotating through hands-on stations, each equipped with a digital scale, overflow can, and density block set to independently measure mass, volume, and density, then compare their results across groups. In a parallel investigation, students will test real water samples — from local canals, the Gordon River, or Gulf-adjacent sites — using handheld salinity refractometers and hydrometers, recording salinity and density data side by side. Students will use this data to predict and then test how mangrove propagules float, orient, and behave in solutions of varying salinity, building toward a written Claim-Evidence-Reasoning explanation of the phenomenon. Every student handles the instruments directly — no group waits on a single shared setup or watches a demonstration from the back of the room.
b) How will this project meet the needs of your students, classroom, and/or school?
A full station set removes the current bottleneck of shared, limited equipment, allowing every group to run independent trials instead of rotating through a single instrument. This matters most for our English Language Learners: repeatable, hands-on measurement tasks paired with vocabulary scaffolding (Spanish cognates, Haitian Creole supports) give ELL students multiple concrete entry points into abstract concepts like density and specific gravity, rather than relying on language-heavy explanation alone. The project also strengthens equity of access to inquiry-based science across my whole class, since every student — not just those closest to the demo table — gets to generate their own data.
c) Teaching strategies or instructional activities:
This unit follows the 5E instructional model (Engage, Explore, Explain, Elaborate, Evaluate), structured through Station Rotation (Catlin Tucker) so groups cycle through instrument-based investigations at their own pace. Students build toward a CER (Claim-Evidence-Reasoning) written explanation of the mangrove propagule phenomenon, supported by sentence frames and ELL vocabulary scaffolds. Specific activities include:
Engage: Observing real mangrove propagules, generating initial questions
Explore: Station-based density and salinity data collection using the new instruments
Explain: Small-group data comparison and vocabulary-supported explanation building
Elaborate: Extending findings to predict propagule behavior in untested salinity conditions
Evaluate: CER writeup assessed against SC.8.P.8.3 and SC.8.P.8.4 criteria
d) How will student participation connect to classroom instruction?
This project is not a standalone activity — it's the hands-on core of my existing density and physical properties unit, directly preceding and reinforcing standards-based instruction on SC.8.P.8.3 and SC.8.P.8.4. The data students collect at these stations feeds directly into their CER writing, which is the same assessment structure I use across all major units this year, so students are practicing a skill they'll reuse repeatedly, not a one-off technique. The coastal/mangrove context also connects forward to earth systems and life science content review later in the year, giving students a concrete touchstone to return to when abstract concepts resurface.
a) Specific improvements expected:
Students will show measurable growth in their ability to independently collect, record, and interpret quantitative data (mass, volume, density, salinity) rather than relying on teacher-led demonstrations. I expect improved mastery of SC.8.P.8.3 and SC.8.P.8.4, specifically in accurately calculating density and correctly classifying substances by physical properties. I also expect stronger CER (Claim-Evidence-Reasoning) writing, since students will be reasoning from data they personally generated rather than data provided to them — this tends to produce more specific, more confident evidence statements. For ELL students in particular, I expect improved content vocabulary retention (density, salinity, displacement, buoyancy) since the hands-on, repeatable station format reinforces new vocabulary through direct physical experience rather than text alone.
b) How success will be measured:
Success will be measured through:
Pre/post comparison of student performance on density- and physical-properties-based FSSA-style assessment items aligned to SC.8.P.8.3/SC.8.P.8.4
Scoring of student CER writeups using a consistent rubric, comparing this unit's scores to CER writeups from earlier units taught with more limited equipment
Station rotation completion and engagement data — whether all groups are completing independent trials in the allotted time, versus previous bottlenecks with shared equipment
Informal observation of ELL student participation and vocabulary use during station work, since these students are often least visible in whole-class discussion but most active in hands-on small-group settings
c) Evidence, observations, student work, or assessments demonstrating impact:
Completed student data tables from each station (mass, volume, density, salinity readings)
Written CER explanations of mangrove propagule float/orientation behavior, scored against a rubric aligned to SC.8.P.8.3/SC.8.P.8.4
Pre- and post-unit assessment scores on density/physical properties items
Each item was selected to remove a specific instructional bottleneck and directly enable the learning goals described in Parts I–III:
Digital pocket scales (8): Give every station group its own precision mass measurement tool, allowing all students to independently collect data rather than sharing a single scale — directly supporting SC.8.P.8.3's requirement that students measure mass and volume themselves.
Overflow cans (8): Enable accurate volume measurement of irregular objects (including mangrove propagules), which is essential for calculating density of non-uniform materials — a step that's impossible to do accurately without displacement equipment.
Density block sets (8): Provide a controlled, repeatable set of materials so every group can test the same variables (same-mass/different-volume, same-volume/different-mass), building the conceptual foundation in SC.8.P.8.4 that density is a property independent of sample size.
Salinity refractometers (16) and hydrometers (16): Let students test real, self-collected water samples and directly connect the abstract concept of density to the concrete, local phenomenon of mangrove propagule float behavior — the anchor phenomenon for the whole unit.
TDS/conductivity meters (4): Add a second, complementary measure of water quality, letting students cross-check and compare instruments — reinforcing measurement precision and data reliability as a science practice.
Calibrated reference mass sets (2): Allow students to verify their own scale's accuracy before trusting their data, turning "using the tool" into "evaluating the tool" — a higher-order science practice that strengthens their CER reasoning about data quality.
Dish tubs, salt, and propagule potting mix: Provide the physical materials needed to actually run the water-based investigations and extend into a growing/observation component tied to the unit.
Every item is reusable across multiple years and multiple units (forces, matter, earth systems), so this isn't single-use consumable spending — it's durable instrumentation that expands hands-on capacity classroom-wide, not just for this one project.
1593.00
8 Digital Pocket Scale, 500g x 0.1g
383.00
8 Overflow Can (aluminum, 5"H x 4" diam)
137.00
8 Density Cube Set (10-piece: steel, aluminum, copper, brass, acrylic, nylon, PVC, oak, pine, poplar)
