Flying Toilet Paper – How to Make a Toilet Paper Launcher

Turn an ordinary leaf blower into an awesome toilet paper launcher as you harness the power of Bernoulli's Principle

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It’s amazing what you can do with differences in air pressure. A tasty drink flows through a straw from a glass up to your mouth. A vacuum pulls dirt from the floor and drops it into a bag. A kite floats on a gentle breeze. A 900,000 pound (410,000 kg) airplane lifts into the air like a bird. Toilet paper flies off the roll and… wait! Toilet paper?! Do it right and you’ll see air pressure differences empty a roll of toilet paper in seconds!

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Here's What You'll Need

  • Full roll(s) of toilet paper
  • Leaf blower
  • Paint roller
  • Duct tape or any strong tape
  • Stick (broom handle, or piece of PVC pipe work great)
  • Adult supervision

Let's Try It

  1. Grab the full roll of toilet paper. Hold the roll so the paper goes over the top of the roll and falls on the side away from you. Unroll a few sections and blow straight across the top of the roll. Surprisingly, the dangling paper lifts upward as you blow. Now, use the hairdryer to blow over the top of the roll. The lifting paper is the reason airplanes fly.

  2. For this Step, a hair dryer probably doesn’t have enough oomph. You need a really big “dryer”: try a leaf blower.

    Grab the stick and slide the full roll of toilet paper over it so the paper unrolls away from you. Turn the blower on high and let the air move over the top of the roll of toilet paper. The roll will be empty in a few seconds! Be sure to clean up the fun when you’re finished.

How Does It Work

This is a wonderful example of Bernoulli’s Principle. In 1738, a Swiss mathematician, Daniel Bernoulli, studied the relationship between the pressure and velocity of a fluid. The Bernoulli Principle states that the pressure of a liquid (in this case, air) falls as its velocity increases. Increasing the velocity over the surface of the paper, lowers the pressure of the air pushing on it.

When you blow across the top of a roll of toilet paper, you lower the air pressure at that point. However, there’s higher pressure under the flapping paper. That’s why the paper lifts up. The same is true for the leaf blower but on a much more powerful scale.

In other words, Bernoulli found that the faster air flows over a surface, the less it pushes on that surface which means it has a lower pressure. The moving air from the leaf blower flows over the top of the toilet paper creating a lower pressure than the surrounding air pushing upward on the bottom side of the toilet paper. The toilet paper is lifted because there is a sufficient number of air molecules striking the lower side of the paper to overcome the downward pull of gravity and the lower air pressure on the upper side.

Real World Application

Airplanes fly because of Bernoulli’s Principle. Air rushing over the top of a curved airplane wing exerts less pressure than air moving against the flat, underside of the wing. So, the relatively higher air pressure beneath the wings provides the upward force, or lift, that enables airplanes, birds, kites, and sail planes to fly.

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