STEM Curriculum for Third Grade

🧩 Builders of the Future: STEM Challenges

An annual plan of 8 challenges that elevate third grade skills toward complex problem solving and systems thinking.

Main Objective of the Plan

To foster an engineer and scientist mindset by empowering third grade students to apply STEM concepts to design innovative, ethical and collaborative solutions.

STEM Disciplines and Skills

Science: Biology (digestive system), simple chemistry (stomach acids), nutrition (macronutrients).
Technology: Guided research (secure websites), creation of digital graphics.
Engineering: Design of a functional model of the digestive system.
Mathematics: Measurement (gut length), calorie estimation (simple), bar graphs (macros).

Critical Thinking: How is food transformed into energy? What happens if a «step» in digestion is missing?
Collaboration: Build the model of the digestive system by «organs» (groups).

Hands-on activities

Functional Digestive Model: Use tubes, plastic bags (stomach), socks (intestine) and liquids (juice) to simulate the food journey.
«Power Lunchbox» planner: Design a weekly lunch menu that balances carbohydrates, proteins and fats.
Macronutrient experiment: Use iodine to detect starch (carbohydrates) in different foods (bread, apple, cheese).

Hybrid/Remote Adaptation (Lunchbox Planner): Students use a Google Slides template to design their weekly menu by dragging food images into the correct boxes.

BrainPop (Digestive System), Google Slides, nutrition apps for children.

Formative Evaluation

Labeled diagram of the digestive system.
Weekly menu rubric (Is it balanced? Is it varied?).
Starch experiment record sheet.

Integration of Ethical Values

Body Consciousness: Respect the body as a complex system that needs good «fuel».
Informed Decision Making: Use data (nutrition) to make healthy decisions.

STEM Disciplines and Skills

Science: Biology (physical/behavioral adaptations), ecology (biomes), fossils.
Technology: Animal research (National Geographic Kids), creation of a mini-terrarium.
Engineering: Design of a «creature» adapted to a specific biome.
Mathematics: Temperature and rainfall measurements (climate data), biome plots.

Creativity: Invent a credible creature based on scientific rules.
Digital Literacy: Synthesize information from multiple web sources.

Hands-on activities

Design-a-Creature: Each group is assigned a biome (e.g., tundra, desert). They must design (draw or model with plasticine) an animal with 3 adaptations that will help it survive there.
Mini-Bioma in Bottle: Build a sealed terrarium (forest/forest biome) or an open terrarium (desert biome) and observe the changes.
Simulation of «Picos de Pinzón»: Use different «picks» (tongs, chopsticks, spoons) to «eat» different «foods» (seeds, gumdrops, rice) and record which pick is best for each food.

Hybrid/Remote Adaptation (Design-a-Creature): Students use a drawing app or even Minecraft to build their creature and its habitat, and record a short video explaining their adaptations.

Seek (by iNaturalist), Nat Geo Kids, Minecraft (Creative Mode).

Formative Evaluation

Presentation of the «creature» (heading of adaptations).
Mini-biome observation diary (weekly records).
Table of data from the «Picos de Pinzón» experiment.

Integration of Ethical Values

Respect for Diversity: Understand that every living being is perfectly adapted to its place.
Conservation: Discuss how climate change threatens these biomes and adaptations.

STEM Disciplines and Skills

Science: Psychology of choice (need vs. want).
Technology: Use of simple spreadsheets (Google Sheets) for budgeting.
Engineering: Design of a financial plan to achieve an objective. Mathematics: Multiplication (profit calculation), subtraction (expenses), simple interest (savings concept).

Critical Thinking: What is more important, a need or a desire? How can I make my money grow?
Future Planning: Establish savings goals.

Hands-on activities

Classification of Need vs. Desire: Give groups cards of items (food, water, video game, brand name clothing, coat) and have them sort and justify them.
$100 Budget: Simulate that they receive $100 per month (toy). They must «pay» fixed expenses (necessities) and then decide how to spend/save the rest.
Simple Interest Simulation: Demonstrate how the «Classroom Bank» adds 10% (e.g., 1 extra coin for every 10) to the money saved each «month» (day).

Hybrid/Remote Adaptation (Budget): Use a simple Google Sheets template where students enter their expenses and the total is automatically subtracted.

Google Sheets (simple template), Banzai Jr. (financial simulator).

Formative Evaluation

Completed budget sheet (Balanced?).
Written justification for a «need vs. want» decision.
Simple calculation of a savings target.

Integration of Ethical Values

Patience and Discipline: Understand the value of saving for a future goal.
Generosity: Discuss the inclusion of «Donate» as a category in the budget.
Responsibility: Own financial decisions.

STEM Disciplines and Skills

Science: Physics (simple circuits, conductors vs. insulators, magnetism, electromagnetism).
Technology: Use of circuit kits (Snap Circuits), simulators.
Engineering: Design of a functional switch, construction of an electromagnet.
Mathematics: Counting (components), measuring (magnetic force - e.g. how many clips it lifts).

Critical Thinking: Why doesn't the light bulb turn on? What materials conduct electricity? How can I make the magnet stronger?
Collaboration: «Debugging» a circuit that does not work as a team.

Hands-on activities

Conductor Laboratory: Create a simple circuit (battery, light bulb, wires). Try different objects (paper clip, eraser, pencil, coin) to see which ones complete the circuit.
Engineering of a Switch: Using paper clips, tacks and cardboard, design a switch that can turn the circuit light on and off.
Homemade electromagnet: Wrap copper wire around an iron nail and connect it to a battery to create a magnet that can be turned on and off.

Hybrid/Remote Adaptation (Conductor Laboratory): Use the Phet.colorado.edu circuit simulator to build circuits virtually and test different materials.

Phet.colorado.edu (Circuit Simulator), Snap Circuits, Tinkercad Circuits.

Formative Evaluation

Record sheet (table) of conductors and insulators.
Functional demonstration of the switch.
Explanation of how to make the electromagnet stronger (more turns, more battery).

Integration of Ethical Values

Security: Discuss electrical safety (never experiment with wall outlets).
Resilience (Growth Mindset): Debugging a circuit is a puzzle, not a failure.

STEM Disciplines and Skills

Science: Water cycle (evaporation, condensation, precipitation), states of matter (melting, freezing).
Technology: Use of thermometers, creation of timelapses.
Engineering: Design of a drip irrigation system, design of a rain gauge.
Mathematics: Measurement (volume, temperature, time), data logging, multiplication (calculation of water use).

Critical Thinking: Where does rain come from? How can we move water efficiently? How do we measure rainfall?
Creativity: Design an irrigation system with recycled materials.

Hands-on activities

Water Cycle Exchange: Draw the sun, clouds and earth on a Ziploc bag. Add some water with blue dye, seal it and stick it to a sunny window. Observe evaporation and condensation.
Ice Race: Investigate the states of matter. What melts an ice cube the fastest (salt, sugar, sun, friction). Measure time.
Drip Irrigation Engineering: Use a plastic bottle, make small holes in it and design it to water a plant slowly and steadily.

Hybrid/Remote Adaptation (Cycle Bag): Perfect activity to do at home. Students take a picture each day for 3 days and place it on a Google Slide to show the process.

Timelapse videos (melting, evaporation), weather apps.

Formative Evaluation

Labeled and explained drawing of the water cycle (based on the bag).
Table of results of the «Ice Race».
Demonstration of the irrigation system (does it work?).

Integration of Ethical Values

Water Conservation: Discuss why drip irrigation is important (saves water) and why fresh water is a precious resource.
Patience: Observe scientific processes that take time (such as the water cycle).

STEM Disciplines and Skills

Science: Logical sequencing, spatial thinking (X, Y, Z views).
Technology: 3D design (Tinkercad), block programming (Scratch - full version).
Engineering: Design process (designing an object for a purpose), digital prototyping.
Mathematics: 3D geometry (cubes, spheres, cylinders), measurement, coordinates (X, Y, Z).

Digital Literacy: Manipulate a 3D environment, understand the 3D printing (slicing) process.
Collaboration: Design a «keychain» of the class in Tinkercad.

Hands-on activities

Scratch Challenge: Go beyond ScratchJr. Create a simple maze game in Scratch (full version) where the character is controlled by arrows and must reach a goal.
Your First Design in Tinkercad: Follow a tutorial to design a simple object with a purpose (e.g. a keychain with your name on it, a pencil holder).
Reverse Engineering: Take a simple object (e.g. a LEGO block) and try to recreate it with its exact measurements in Tinkercad.

Hybrid/Remote Adaptation (Tinkercad): Tinkercad is web-based, so it works seamlessly. Students share the public link of their design in a Padlet for a virtual «3D Gallery».

Scratch (web), Tinkercad (web), Padlet.

Formative Evaluation

Functional maze game in Scratch.
.stl file or Tinkercad link of the 3D design (requirements checklist).
Self-assessment: What was the most difficult thing about thinking in 3D?

Integration of Ethical Values

Intellectual Property: Discuss the difference between «copying» a design and «remixing» (improving) one.
Accessibility: Discuss how 3D printing can create solutions for people with disabilities.

STEM Disciplines and Skills

Science: Product life cycle («cradle to grave»), decomposition, composting (biology).
Technology: Investigate the carbon/water footprint of a single product.
Engineering: Design of a classroom composting system. Mathematics: Measurement (weight, volume), time (decomposition), pie charts (garbage composition).

Creativity: Find alternative uses for «waste».
Critical (Systemic) Thinking: Understand that «throwing away» is not the end of the story.

Hands-on activities

Biography of an Object: Choose an object (e.g. plastic bottle, cotton t-shirt) and investigate (guided) its life cycle: where the materials come from, how it is made, how it is discarded.
Bottle Composter: Construct a mini-composter in a 2 liter bottle, alternating layers of «greens» (fruit/vegetable scraps) and «browns» (dry leaves, cardboard). Observe decomposition.
Garbage Audit Level 3: Repeat the 2nd grade audit, but this time, create a detailed plan for «Refuse», «Reduce», «Reuse», «Recycle» and «Compost» (Rot).

Hybrid/Remote Adaptation (Object Biography): Students create a 4-panel «comic» on Google Slides that tells the story of their object (Birth, Life, Disposal, Possible Reincarnation).

Google Slides, cradle-to-grave videos, carbon footprint apps.

Formative Evaluation

Presentation of the «Biography of an Object».
Observation diary of the composter (temperature, appearance).
Garbage reduction plan proposal (based on graphs).

Integration of Ethical Values

Sustainability: Understand the long-term impact of our consumption.
Cyclical Thinking: Seeing «waste» as «resources» in the wrong place.
Global Consciousness: Understand that our waste affects other places and people.

STEM Disciplines and Skills

Science: Social observation, ergonomics (simple).
Technology: 3D design (Tinkercad) for accessibility, accessibility apps (screen reader).
Engineering: Universal Design, rapid prototyping, human-centered design.
Mathematics: Measurement (ramp angle, door width), scale, proportions.

Collaboration: Co-design solutions with empathy.
Critical Thinking (Empathy): How would someone who cannot see use this? How would someone in a wheelchair get in?

Hands-on activities

Accessibility Audit: Tour the school, but this time with simulated «disabilities» (e.g., one arm tied, blindfolded with a guide, sitting in a wheelchair if safe) and identify barriers.
Inclusive Solution Prototype: In groups, choose a barrier encountered and design a solution (e.g., a better door opener, a ramp). Prototype with cardboard.
Inclusive 3D Design: Use Tinkercad to design an object that helps someone (e.g. a thicker grip for a stylus, a braille button).

Hybrid/Remote Adaptation (Audit): Students conduct the audit in their own home or building (with permission). They take photos of 3 «barriers» (e.g., thick carpet, high step) and upload them to a Jamboard.

Tinkercad, Jamboard, Universal Design videos.

Formative Evaluation

Accessibility Audit Report (list of barriers).
Presentation of the cardboard prototype (does it solve the problem?).
Tinkercad design (does it fulfill its purpose of helping?).

Integration of Ethical Values

Empathy as a Design Engine: Putting the needs of others first.
Inclusion: Understand that good design works for *everyone*, not just the majority.
Social Justice: See accessibility as a right, not an extra.