Buoyancy Science Experiment | Cartesian Bottle Diver STEM Lab Activity

Bring physics to life with this exciting hands-on buoyancy science experiment using a classic Cartesian diver in a bottle STEM lab activity! Students will explore the concept of buoyancy, pressure, and density through a simple, engaging, and unforgettable demonstration.

This interactive science lesson helps learners see physics in action as they observe how squeezing a bottle causes a “diver” to sink—and releasing pressure makes it rise again!

🧪 What Students Will Do:

✨ Build a simple Cartesian diver using a bottle, straw, water, and paper clips

✨ Observe how pressure changes affect buoyancy

✨ Watch the diver sink and rise based on bottle pressure

✨ Make predictions, record observations, and draw conclusions

✨ Engage in real-world scientific thinking and experimentation

📘 Includes:

✔ Step-by-step hands-on STEM science experiment instructions

✔ Printable science journal pages

✔ Prediction, observation, and conclusion prompts

✔ Student recording sheets to support the scientific method

✔ Easy prep teacher-friendly activity

🧠 Science Concepts Covered:

• Buoyancy and density
• Pressure and force
• Scientific method (predict, observe, conclude)
• Physics fundamentals through hands-on learning
• Critical thinking and inquiry-based science

🎯 Perfect For:

✔ 2nd–6th Grade Science

✔ Homeschool STEM lessons

✔ Earth & physical science units

✔ Science centers and stations

✔ Sub plans and enrichment activities

✔ Hands-on experiential learning

💡 Why Teachers Love It:

This experiment transforms abstract physics concepts into a visual, hands-on STEM experience that students remember. It encourages curiosity, engagement, and scientific reasoning—all through a simple bottle experiment!

4 page PDF print file

🌟 Extend the Learning

Want more hands-on, video-based STEM science lessons like this one?

Explore our full 30 Science Experiment Mega Bundle (with labs + video lessons + printable journals) here:

👉 https://www.teachmetruth.com/courses/science-bundle