demonstrations:bernoullis_toilet_paper

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

  1. Hold a toilet paper roll horizontally on a stick.
  2. Blow steadily across the top of the roll. Observe how the paper lifts slightly.
  3. Repeat the experiment using a leaf blower directed across the top of the roll.
  4. Watch as the toilet paper unrolls and flies upward, high enough to resemble toilet papering a tree.

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.)