Physics Project - Properties of a Tsunami

[shootingrubbe]

Hello,

Here is a Physics Project I recently did on Tsunamis.

Let me know what you think:

http://www.vimeo.com/2878780

Thanks.

 

[turin]

I don't understand how pulling a large solid flap out of the water in any way resembles a disturbance isolated to the ocean floor. Furthermore, this simulated disturbance spans across the entire width of the tank. Does a seismic disturbace span the width of the ocean? Also, how did you compensate for the curvature of the Earth's surface, and dissipation due to spreading in 2 dimensions?

 

[Danger]

Welcome to PF, Shootingrubber.
Your presentation, visually, was both very impressive and very irritating. Too much with the cutesy text manipulation. I do recognize the talent that went into developing it, but that's not what someone wants to see in a technical video.
That having been said, Turin brought up a couple of key points. A seismic disturbance, which is the usual cause of a tsunami, is not a linear phenomenon. It radiates from a central location, and the waves are not confined to a particular pathway. The initial energy, therefore, obeys the inverse square law the same way that any other 3-dimensional activity does. (This would be for something like a depth-charge going off; I don't know how the dynamics are affected when the crust of the Earth is taking up a portion of that volume. There will be 'echoes' and secondary tremors.)
I suspect that this thread should be moved to the 'Other Sciences' sub-forum for Earth Science.

 

[turin]

It radiates from a central location, and the waves are not confined to a particular pathway. The initial energy, therefore, obeys the inverse square law the same way that any other 3-dimensional activity does.

However, I expect the power density of the eventual expanding wave, being essentially a 2-D phenomenon, to obey the 1/r law rather than the 1/r^2 law. The power is essentially distributed over a circle, and so it must be distributed over a length of 2*pi*r, not an area of 4*pi*r^2.

 

[LURCH]

As others have pointed out, there are definitely some problems. However, that having been said, there were also several things I liked about the video. In particular, I appreciated the fact that the wave progress was shown in slow motion, with the relevant measurements displayed.

Regarding the set up:
I realize that the project is done, but this might be something you can do for your own enjoyment. You know those toys that have a spring and a suction cup on the bottom? You know the type; he pushed down on the toy to compress the spring until the suction cup sticks to surface. After a while, the suction cup loses its seal in the spring causes the toy to pop up. Could you stick something like that to the bottom of your insert? It would be interesting to see what happens when a small part of the bottom of your tank suddenly raises by just a few inches (rather than being pulled completely up out of the water).

BTW; exactly what physics class was this project for?

 

[shootingrubbe]

As others have pointed out, there are definitely some problems. However, that having been said, there were also several things I liked about the video. In particular, I appreciated the fact that the wave progress was shown in slow motion, with the relevant measurements displayed.

Regarding the set up:
I realize that the project is done, but this might be something you can do for your own enjoyment. You know those toys that have a spring and a suction cup on the bottom? You know the type; he pushed down on the toy to compress the spring until the suction cup sticks to surface. After a while, the suction cup loses its seal in the spring causes the toy to pop up. Could you stick something like that to the bottom of your insert? It would be interesting to see what happens when a small part of the bottom of your tank suddenly raises by just a few inches (rather than being pulled completely up out of the water).

BTW; exactly what physics class was this project for?

This was for my Grade 11 Physics class.

Thanks for your guys' comments. They are really appreciated.