Bernoulli’s Toilet Paper
Materials: ★★★ Requires materials not commonly found in school laboratories
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Pressure and Fluids
Alternative titles: Leaf Blower Bernoulli Experiment
Summary
This demonstration shows how Bernoulli’s principle can lift and propel toilet paper. Blowing across the top of a roll lifts it slightly, while using a leaf blower creates a strong stream of fast-moving air that launches the toilet paper high into the air.
Procedure
- Hold a toilet paper roll horizontally on a stick.
- Blow steadily across the top of the roll. Observe how the paper lifts slightly.
- Repeat the experiment using a leaf blower directed across the top of the roll.
- Watch as the toilet paper unrolls and flies upward, high enough to resemble toilet papering a tree.
Links
Bernoulli's Principle Demonstration: Toilet Paper - SDPB:
Leaf Blower Toilet Paper Fun! Bernoulli's Principle | Mister C TV - learningscienceisfun:
📄 Physics Force - University of Minnesota: https://physicsforce.umn.edu/content/toilet-paper-tree-0
Variations
- Try using different air sources (hair dryer, fan, compressed air) to compare effects.
- Test with lighter or heavier paper products (tissue paper vs. paper towels).
Safety Precautions
- Keep a safe distance when using a leaf blower.
- Do not aim the blower at people or fragile objects.
- Pick up toilet paper afterward to avoid littering or creating slipping hazards.
- Use protective eyewear if working close to high-speed air streams.
Questions to Consider
- Why does blowing across the paper cause it to rise? (The faster-moving air above reduces pressure, so higher pressure below pushes the paper up.)
- Why is the leaf blower more effective than just blowing with your mouth? (It produces a much faster airflow, creating a stronger pressure difference.)
- How does this relate to airplane wings? (Air travels faster over the curved top surface of a wing, lowering pressure and creating lift.)
- Can Bernoulli’s principle alone explain all lift? (Not entirely—other factors like circulation and angle of attack also play roles in real aerodynamics.)