Tonight is the Hallowbrook Harvest, and the town’s glowing Pumpkin Beacon—the lantern that keeps mischievous spirits from pranking the candy supply—has dimmed. The only way to recharge it is to airlift a ghost balloon up to the Witching Line so it can soak up protective moonlight.

Your team has been recruited by the Bureau of Unnatural Lift (B.U.L.) to build a Spectral Lifter: a device that captures spirit gas (okay, okay… it’s CO₂ from a safe reaction) to inflate a ghost balloon to the target height fast and efficiently.

You can also find this activity at a discount inside my - Halloween Science Activities and Investigations Growing Bundle.

Turn a bottle, balloon, and household ingredients into a full engineering-design challenge! Students test how different amounts of baking soda affect CO₂ gas production and balloon lift—then analyze which setup creates the highest and most stable “ghost balloon.”

The lab emphasizes variables, fair testing, repeated trials, data collection, graphing, and CER writing—perfect for middle school science, Halloween week, or STEM design days.

What Students Do

• Identify independent, dependent, and controlled variables
• Write a testable hypothesis predicting optimal reactant ratio
• Conduct trials at five reactant levels (0.5, 1.0, 1.5, 2.0, 2.5 tbsp baking soda)
• Measure maximum lift height (cm) and time to reach target height (s)
• Record, average, and graph results (Avg Max Height vs Reactant Amount)
• Construct a Claim–Evidence–Reasoning (CER) explanation for best performance

What’s Included

• Teacher Guide: setup, safety, pacing, and background science (gas production, reaction rate, pressure, and lift).
• Student Packet: clear step-by-step procedures, data tables for five reactant levels, and repeatable trials.
• Graphing & Summary Pages: labeled template with trendline prompt and annotations for the best-performing mix.
• Analysis & Model Answers: exemplar responses explaining reaction efficiency, limiting factors, and sealing quality.
• Rubric: simple 20-point rubric for Design, Data, Graphing, CER, and Collaboration.

Materials Needed

Small plastic bottle (500 mL), balloon, baking soda, vinegar, funnel, measuring spoons, ruler/tape measure, string, tray, goggles, paper towel, and optional food coloring for the “ghost effect.”

Why Teachers Love It

• Low-cost, high-engagement activity perfect for fall or Halloween or anytime you are looking at reactions.
• Emphasizes true scientific testing and engineering design.
• Generates graphable, repeatable data for quantitative analysis.
• Ideal for one class period with flexible extensions for optimization

I also have the following STEM Labs in My Store:

• Blow Cup Challenge STEM Lab
• Paper Table STEM Lab
• Pendulum STEM Lab
• Parachute STEM Lab
• Catapult STEM Lab
• Paper Airplane - Angle of Attack STEM Lab
• Bottle Flip STEM Lab
• Paper Helicopter STEM Lab
• Yeast Balloon STEM Lab
• Ghost Balloon STEM Lab

NGSS alignment

• MS-PS2 Motion and Stability: Forces and Interactions (gravity, drag, balanced/unbalanced forces)
• MS-ETS1 Engineering Design (defining problems, testing solutions, optimizing designs)
• Science & Engineering Practices: Planning and Carrying Out Investigations;
• Analyzing and Interpreting Data; Using Mathematics and Computational
• Thinking; Engaging in Argument from Evidence
• Crosscutting Concepts: Cause and Effect; Structure and Function