Grade 3 · Human Systems Science III
Grade 3 learners reason about systems with multiple parts, track flows of resources, compare outcomes, and explain cause-and-effect using evidence. They use simple models, scaled representations, and recorded data to support explanations. Students are expected to answer not only what changed, but why it changed.
Continuing Anchor Ideas
Explicitly reinforced and expanded, named often and used as reference points across domains.
Water, energy, food, materials, and information flow through systems.
Students track flow and explain what changes when the flow is disrupted.
Systems are made of parts that work together.
Students identify parts, roles, and connections using models and diagrams.
Human-designed systems affect natural systems and are affected in return.
Students compare impacts and explain system interactions using evidence.
Choices involve tradeoffs and consequences.
Students compare outcomes and justify decisions in design challenges.
Problems can be understood and improved through modeling, testing, and redesign.
Students test, record results, analyze failure, then redesign and explain why changes worked.
Students can work with simple models and scaled representations, track flows of resources, and use recorded data to support explanations. They are expected to explain cause and effect, including why a change occurred and what evidence supports the claim.
What Grade 3 adds to the system: systems are explicit, named, and modeled, flows and consequences are expected, design includes failure and redesign, earlier concepts scaffold rather than repeat.
Grade 3 Standards by Domain
Students model systems, track flows, compare outcomes, and explain why changes occurred using evidence.
3-HS1
Water Systems and Resource Flow
Clean Water & Sanitation
Flow
Optimize
- 3-HS1.1 Students model how water moves through natural and human systems.
- 3-HS1.2 Students explain how water availability affects living things and communities.
- 3-HS1.3 Students investigate causes of water contamination.
- 3-HS1.4 Students design and test systems that improve water access or quality.
Hands-on STEM expectation
Watershed models, water flow maps, contamination simulations, filtration redesign.
3-HS2
Energy Systems and Transfer
Affordable & Clean Energy
Transfer
Tradeoffs
- 3-HS2.1 Students identify sources of energy and how energy moves through systems.
- 3-HS2.2 Students investigate how energy is transformed during use.
- 3-HS2.3 Students compare energy systems based on effectiveness and impact.
- 3-HS2.4 Students design and test devices that transfer energy efficiently.
Hands-on STEM expectation
Energy chain models, mechanical transfer experiments, efficiency comparisons.
3-HS3
Health, Environment, and System Interaction
Good Health & Well-Being
Feedback
Prevention scale
- 3-HS3.1 Students explain how environment, behavior, and health are connected.
- 3-HS3.2 Students investigate how diseases spread through systems.
- 3-HS3.3 Students analyze how prevention reduces system-wide impacts.
- 3-HS3.4 Students design strategies to improve health outcomes in communities.
Hands-on STEM expectation
System maps of disease spread, intervention modeling, prevention testing.
3-HS4
Infrastructure and Design Systems
Industry, Innovation, & Infrastructure
Reliability
Failure-redesign
- 3-HS4.1 Students identify infrastructure systems that support daily life.
- 3-HS4.2 Students explain how infrastructure moves resources or people.
- 3-HS4.3 Students analyze how system failure affects communities.
- 3-HS4.4 Students design infrastructure improvements using models.
Hands-on STEM expectation
Bridge and pipeline models, failure testing, redesign challenges.
3-HS5
Community Systems and Sustainability
Sustainable Cities & Communities
Integration
Tradeoffs
- 3-HS5.1 Students describe how community systems are connected.
- 3-HS5.2 Students analyze how growth changes communities.
- 3-HS5.3 Students compare community designs for sustainability.
- 3-HS5.4 Students design community features that improve quality of life.
Hands-on STEM expectation
City models, resource distribution simulations, planning challenges.
3-HS6
Production, Use, and Waste Systems
Responsible Consumption & Production
Resource limits
Efficiency
- 3-HS6.1 Students trace products from raw materials to disposal.
- 3-HS6.2 Students explain how production choices affect resources.
- 3-HS6.3 Students analyze waste impacts on systems.
- 3-HS6.4 Students design improvements to reduce waste or resource use.
Hands-on STEM expectation
Supply chain mapping, material flow charts, redesign challenges.
3-HS7
Water Ecosystem Systems
Life Below Water
Dynamics
Intervention
- 3-HS7.1 Students model interactions within water ecosystems.
- 3-HS7.2 Students investigate how changes affect ecosystem balance.
- 3-HS7.3 Students analyze human impacts on water systems.
- 3-HS7.4 Students design solutions to restore ecosystem balance.
Hands-on STEM expectation
Food web models, disturbance simulations, restoration planning.
3-HS8
Land Ecosystem Systems
Life on Land
Stability
Restore
- 3-HS8.1 Students model interactions in land ecosystems.
- 3-HS8.2 Students investigate how land use changes affect systems.
- 3-HS8.3 Students analyze causes of habitat disruption.
- 3-HS8.4 Students design strategies to protect or restore land systems.
Hands-on STEM expectation
Erosion models, habitat fragmentation simulations, conservation design.
Grade 3 throughline: students model systems and flows, explain consequences, analyze failure, then redesign and justify improvements using evidence.
Design and Practice Standards
Applied continuously, students ask testable questions, collect measured data, improve models and designs, and communicate reasoning.
- 3-DSP1 Students ask testable questions about systems.
- 3-DSP2 Students plan investigations and collect measured data.
- 3-DSP3 Students use evidence to improve models and designs.
- 3-DSP4 Students communicate explanations using diagrams, charts, and written reasoning.
What Grade 3 accomplishes
Systems are explicit and modeled, flow and consequence are expected, design includes failure and redesign, earlier concepts scaffold rather than repeat, students are prepared for deeper resource and impact analysis.