Why Does a Marble Fall Faster in a Pool Than in a Narrow Tube?

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A marble falls faster in a swimming pool than in a narrow tube due to the difference in water displacement. In a pool, the water can move freely, allowing the marble to accelerate quickly. In contrast, in a narrow tube, the water is restricted, causing slower displacement and increased resistance against the marble. This concept is similar to the effect of a firecracker on a ping-pong ball in open space versus in a confined tube. The discussion highlights the importance of water movement and resistance in determining the speed of falling objects.
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Can anyone give me an explanation of why a marble dropped into a swimming pool will fall faster than if you drop a marble into a water filled tube with a diameter only slightly larger than the marble itself (presume it doesn't touch the walls of the tube). It's something to do with how quickly water can be displaced, but I can't come up with a good explanation.

Thanks,
 
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You're pretty much there. Try thinking of a similar but different scenario. What would be the effect of setting off a firecracker beside a ping-pong ball as opposed to putting them both into a narrow tube and lighting it? Why?
 
Thanks, I understand now :)
 

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