Turning Bucket

Let's take a look!

Watch the video on YouTube.

Experimental procedure and explanation:

• Place a bucket containing water on a turntable.
• Spin it fast.
• When the spinning motion stabilizes, stop the spin by hand, and then immediately let it go.
• The bucket will start to spin again. Why does this happen?
• After the bucket spins for a while, the water inside will spin with the bucket.
• Even after you stop the bucket, the water inside will keep spinning for a while. Because water deforms freely, it does not move along with the bucket, and because the water inside is spinning, the bucket will start to spin again once you let go of the bucket.

[Keywords]	deformation of fluid
[Reference]	“The Wonders of Flow,” Japan Society of Mechanical Engineering, Koudansha Blue Backs, pp. 12-15