Students will investigate non-Newtonian fluids by creating oobleck and testing how different types of force affect whether it behaves like a solid or a liquid. Using cornstarch and water, students observe how fast force causes oobleck to act solid while slow force allows it to flow like a liquid.

Through repeated trials, careful observation, data collection, and a CER, students discover how force changes viscosity and why oobleck does not follow the same rules as typical liquids — while building core lab and scientific reasoning skills.

Learning Targets

• Plan and carry out a controlled investigation with repeated trials
• Observe and compare oobleck behavior under fast and slow force
• Identify patterns between force type and material behavior
• Construct a CER explaining how force affects oobleck using particle motion and viscosity concepts
• Identify variables, maintain controls, and improve test consistency

What’s Included

Teacher Guide

Setup tips, safety notes, cleanup guidance, and clear background explanations of non-Newtonian fluids. Includes guidance for standardizing mixture ratios, force application methods, and testing procedures to ensure fair comparisons.

Student Packet

Hypothesis prompt, variables chart, step-by-step mixing and testing instructions, 5-trial data table for fast and slow force, observation recording pages, and structured CER response.

Analysis & Answer Key

Expected patterns (fast force → solid behavior, slow force → liquid behavior), sample observations, detailed reasoning examples, common error sources, and a full model CER paragraph grounded in particle motion and shear thickening concepts.

Rubric

Assesses experimental design, procedure consistency, observation quality, scientific reasoning, CER strength, collaboration, and safety — fully aligned with middle-school science practices.

Why Teachers Love It:

• Low-prep & inexpensive — just cornstarch and water
• High engagement — students love the strange, hands-on texture and behavior
• Builds core lab skills: variables, controls, observation, consistency
• Strong physical science + material science crossover
• CER requires real evidence-based reasoning, not guesswork
• Perfect for stations, STEM days, electricity units, or sub-friendly lessons

➡️ You can get this STEM as well as all my other ones in this series inside my STEM Investigations Growing Bundle. As more labs are added, the price will increase. CLICK HERE to have a look

Best For

Physical Science (matter, viscosity, forces), lab skills, CER writing, properties of materials, STEM challenges, or sub-friendly hands-on lessons.

Materials Needed

Cornstarch, water, mixing bowls or cups, spoons/stir sticks, trays or plates, paper towels, student packet (included). Optional: timer, ruler, food coloring.

Estimated Timing

1 class period for mixing → testing → data collection → CER writing
Add 10–20 minutes for discussion questions and improvement proposals

➡️ You can get this activity inside my STEM Investigations Growing Bundle.

I also have the following STEM Labs in My Store:

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• Newton's 2nd Law of Motion STEM Lab - Balloon Rocket
• Newton's 3rd Law of Motion STEM Investigation - Thrust vs Nozzle Size
• Electromagnet - Coil Turns vs Magnetic Strength
• Oobleck: Force vs Flow — Non-Newtonian Fluids

NGSS alignment

MS-PS1-2, MS-PS2-2 (properties of matter, forces & interactions)

Practices: Planning & Carrying Out Investigations; Analyzing Data; Constructing Explanations; Argument from Evidence

Assessment

Use the included rubric to score experimental design, procedure consistency, observation quality, scientific reasoning, CER strength, collaboration, and safety.