Garden Eel 2

Let's take a look!

What type of experiment is this?

Experimental procedure and explanation:

• We previously released a video called ‘Garden Eel’, which used the Cartesian driver concept. This was one that sank when force was applied and moved in the same manner as an ordinary float.
• This time, we made a spotted garden eel that floats up and out of its hole when force is applied, in the opposite movement to this one.
• The spotted garden eel was developed in the same way as before. We block the mouth of one end of the bendable straw and attach a weight (using a nut) to the other end. Adjust the amount of water that is sucked up inside so that it sinks to the bottom when placed in water. At this point, the spotted garden eel should be just on the verge of floating or sinking.
• It is placed into its burrow and then placed into a jug filled with water. We place a rubber balloon (tip slightly trimmed off) over the mouth and secure it with a thick rubber band.
• When the end of the rubber balloon is pulled upward, the spotted garden eel emerges from the hole. The internal volume increases and the air pressure inside decreases. The volume of air increases, buoyancy increases, and the spotted garden eel floats up.
  Next, when the force of pulling on the rubber balloon is loosened, the volume of air inside decreases and the buoyancy is reduced, causing the spotted garden eel to sink and return to its burrow.
• This experimental video was produced with the support of JSPS Grant-in-Aid for Scientific Research 18K03956.

[Keywords]	Buoyancy, cartesian diver, negative pressure
[Related items]	Garden Eel, Cartesian diver that floats when force is applied
[Reference]	Ryozo Ishiwata, "The Wonder of Flow," Kodansha Blue Backs, p. 34-37, p. 42-47 Ryozo Ishiwata, "Illustrated Fluid Dynamics Trivia", Natsume Publishing, P14-15, P34-35

◀　Back Next　▶