Re: natural disasters,weather phenomena

[Dan Burns <kilroi@lghs.net>]

We do a very similar lab with the ninth grade Earth/Space science students at
Los Gatos High School. Two years ago, while discussing the lab results, we had
a 4.9 earthquake. Just after the quake a student yelled "Look!" while pointing
toward our model buildings. Sure enough, only the medium height building was
still shaking. It is rare for nature to be so coorperative. However, I was
worried because our next lab was about volcanoes!

Dan Burns

Hugh Haskell wrote:

> > Heidi,
> >
> >       Buildings in high risk zones must be designed to take a beating
> > when an earthquake hits. A couple factors to consider are how large are my
> > earthquakes, and how tall is my building (how far up is the center of mass
> > located). We can duplicate an earthquake simply by shaking a table or piece
> > of wood so the driving is not a big problem. A building can be recreated by
> > simply putting a mass (a solid sphere) onto a thin metal pole (of
> > negligible mass  and ‰ 1/16").
> > This pole is then inserted into a hole into a pice of wood. We now have a
> > simulated center of mass for a building of some height. If we shake the
> > board lightly the mass should react differently then if the board is shaken
> > harder. Now try making a few "buildings" of different heights and see how
> > they compare in different earthquake situations. This is just an idea and I
> > would like to hear if you think it has any validity.
> >
> >                                               Enjoy,
> >
> >                                               Nils
> >
> > P.S. Great choice of major!!
>
> Nils, I don't know what Heidi will think of your idea, but I think it is an
> excellent one, especially as an open-ended project for young students.
> There are lots of possibilities for invesitgation here: amplitude of
> shaking, frequency of shaking, length and/or stiffness of the posts, mass
> of the balls, relationship between stiffness of the supporting rod and the
> mass of the ball, sudden shock or continuous oscillations. The list goes
> on. The students could video-tape their experiments and put together a
> presentation that could be quite dramatic. The students should research the
> types of earth motions that have occurred during various historical
> earthquakes, and then figure out how best to simulate them on the quake
> table. They could also simulate various types of consturction that have
> been designed to withstand earthquakes. A class could be broken up into
> small groups, with each group investigating one aspect of the process and
> then as the culmination of their project, they present their results to the
> rest of the class.
>
> It would certainly be useful if the students had spent some time studying
> the phenomenon of resonance before undertaking this investigation, but not
> in such depth that they could predict everyhting that would happen.
>
> This idea has lots of possibilities. Heidi, I would like to hear what you
> end up doing, whether or not it uses this scheme or not, and I suspect
> others on this list would also.
>
> Happy physics,
>
> Hugh
>
> Hugh Haskell
> <mailto://hhaskell@mindspring.com>
>
> Let's face it. People use a Mac because they want to, Windows because they
> have to..
> ******************************************************