Balloon in a plastic bottle

Let's take a look!

What type of experiment is this?

Experimental procedure and explanation:

• We place a yellow balloon inside a plastic bottle. The balloon is connected to the outside atmospheric pressure by a straw, and the pressure inside the balloon is always at atmospheric levels.
• We cut the bottom side of the plastic bottle short, cover it with a rubber balloon, and secure it with duct tape.
• When no force is applied to the rubber balloon on the lid, both the inside and outside of the yellow balloon are at atmospheric pressure, and they will not inflate.
• When the tip of the rubber balloon on the lid is pulled downward, the air inside the plastic bottle expands and the pressure decreases. The pressure at this time is less than atmospheric pressure and is called "negative pressure.” The inside of a yellow balloon is at atmospheric pressure and the outside is less than atmospheric pressure (negative pressure), and the balloon expands from due to the difference in pressure between the inner and outer surfaces.
• This experimental video was produced with the support of JSPS Grant-in-Aid for Scientific Research 18K03956.

[Keywords]	Pressure, negative pressure
[Reference]	Ryozo Ishiwata, "The Wonder of Flow," Kodansha Blue Backs, P34-37. Ryozo Ishiwata, "Illustrated Fluid Dynamics Trivia", Natsume Publishing, p. 34-35.

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