Dropping a circular paper into a cylinder

Let's take a look!

What type of experiment is this?

Experimental procedure and explanation:

• A large graduated cylinder is used in the “Dropping a horizontal disk into a cylinder” experiment. Here, let us experiment with materials that are available or can be made at home.
• Cut two 1.5-liter carbonated drink PET bottles and connect them to make a cylinder. This work is dangerous, so let us do it under adult supervision.
• Cut the paper (copier paper in this video) into a circular shape and drop it inside.
• Level the paper and gently release it into the cylinder; it slowly falls while remaining horizontal.
• Air from the bottom flows through the gap between the paper and the cylinder; however, because the gap is narrow, the air passes slowly because of the viscous action. Therefore, the paper falls slowly.
• Next, cut a tissue paper in a circular shape and perform the experiment. Please cut the tissue paper carefully so that it does not wrinkle. It also falls slowly without breaking.

[Keywords]	Viscosity, Air resistance
[Related items]	Dropping a horizontal disk into a cylinder
[Reference]	“The Wonders of Flow”, Japan Society of Mechanical Engineering, Kodansha Blue Backs, P19.

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