Students will investigate Newton’s 3rd Law of Motion by testing how changing the nozzle opening of a water-powered bottle jet affects the distance it travels. Using a plastic bottle, interchangeable bottle-cap nozzles with different hole diameters, and a simple launch cradle, students observe how the backward push of water creates an equal and opposite forward force. Through repeated launches, distance measurement, class averages, graphing, and a CER, students discover how nozzle size changes thrust and why action–reaction force pairs drive all propulsion systems.

Learning Targets

• Plan and carry out a controlled investigation with repeated trials
• Measure travel distance and calculate class averages
• Graph class data to compare how nozzle diameter affects thrust
• Construct a CER explaining the relationship between nozzle size and forward motion using Newton’s Third Law
• Identify variables, maintain controls, and improve test consistency

What’s Included

• Teacher Guide

Setup diagrams, safety notes, launch-zone management tips, and clear background explanations of Newton’s Third Law (action–reaction force pairs). Includes guidance for standardizing bottle volume, nozzle attachment, fill levels, launch angle, and release technique to ensure fair comparisons.

• Student Packet

Hypothesis prompt, variables chart, step-by-step build/setup instructions, 3-trial data table per nozzle size, average-distance calculations, comparison table, graphing task, and structured CER response.

• Class Data & Graphing Pages

Class totals chart, bar-graph template (“Average Distance vs Nozzle Diameter”), labeled-axes lines, and a caption prompt requiring students to identify which nozzle produced the greatest thrust using numerical evidence.

• Analysis & Answer Key

Expected patterns (smaller openings → longer thrust / greater distance), sample calculations, reasoning examples, possible error sources, and a full model CER paragraph grounded in Newton’s Third Law.

• Rubric

Assesses experimental design, data accuracy, graph quality, CER strength, and teamwork/safety—fully aligned with middle-school science practices.

Why Teachers Love It:

• Easy prep — just bottles, water, tape, and bottle caps
• Highly engaging visual results (dramatic distance differences!)
• Builds core lab skills: identifying variables, consistency control, measuring & averaging
• Perfect introduction to forces, propulsion, rockets, and Newton’s 3rd Law
• Graphing + CER require real evidence-based reasoning
• Great for stations, engineering challenges, or sub-friendly physics 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 (forces, motion, propulsion), lab skills, graphing, CER writing, Newton’s 3rd Law, engineering design, or sub-friendly hands-on lessons.

Materials Needed

Plastic bottle, water source, 2–3 bottle caps with drilled holes of different diameters, tape/sealant, launch cradle (simple cardboard/wood stand), measuring tape, student packet (included). Optional: scale, safety goggles, outdoor launch area.

Estimated Timing

1 class period for setup → launches → class graph.
Add 20–30 minutes for CER writing, 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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• Paper Helicopter STEM Lab
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• Adaptations by Design - Extreme Environments STEM Lab
• Newton's 1st Law of Motion STEM Lab - Penny and Index Card - Inertia Test
• Newton's 2nd Law of Motion STEM Lab - Balloon Rocket
• Newton's 3rd Law of Motion STEM Investigation - Thrust vs Nozzle Size

NGSS alignment

MS-PS2-2, MS-PS2-1 (forces & motion, Newton’s 1st Law)

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

Assessment

Use the included rubric to score environment understanding, adaptation quality and plausibility, scientific accuracy, CER strength, and class data/graph work.