Toilet Paper Spreader
| Material: |
one or two rolls of toilet paper, a rod or wooden dowel to hold the toilet paper, and an electric powered leaf blower works GREAT |
| Directions: | Place the toilet paper on the rod making sure that very little friction is
created as it rolls off. Also make sure that the paper is positioned so it will unroll
from the top and away from you. Next turn on the blower and lower the air stream so it creates a low pressure cell just above the top of the toilet paper. You should get at least a 15 foot streamer coming off your roll. (Hint: It works better to load the toilet paper onto the rod or dowel so it unrolls from the top.) |
| Safety Concerns: | None. |
| Questions: | What happened? Why did the toilet paper unroll? |
| Concepts: | Air, whether moving or stationary, exerts pressure. Moving air, created by blowing in this activity, has a lower pressure than stationary air (Bernoulli's Principle). The faster the air moves, the lower the pressure it exerts. So in this activity, the difference in air pressure causes the toilet paper to lift and to be carried aloft. Application: The fact that air planes fly is an application of Bernoulli's Principle. The wings of the airplane are shaped to have a curvature. The top surface has a larger curvature than the bottom surface. As a result, the air moving over the top of the wing has to travel further than the air flowing under the bottom. Since the air must reach the other side of the wing at the same time, the top must travel faster. This creates a low pressure zone and thus creates lift. |