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Was the real sediment also in mineral oil or was it in water?

Dave Smith
Da Vinci Science Center

On Mon, Aug 18, 2008 at 8:21 PM, Clifford Wagner
<[log in to unmask]>wrote:

> ISEN-ASTC-L is a service of the Association of Science-Technology Centers
> Incorporated, a worldwide network of science museums and related
> institutions.
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> *****************************************************************************
>
> I protoyped and made this device in 1983 at the Franklin Institiute for our
> Changing Earth Exhibit.  Hadn't seen it before then, but maybe it did exist
> before that.    There were three 3inch diameter plexiglass tubes  about 18
> inches long, each on it's own vertically oriented turntable.   They had 1/4
> thick walls.
> Their ends were capped with plexiglass and Orings with threaded brass rods
> running the length of the tube holding the ends on.  Here's why to do three
> tubes on three turntables:  The first has as a label "Same size, different
> density"  and has about 30 steel and 30 nylon balls @ 3/8 diameter.  They
> are in Mineral oil bought at the drug store.  Turn the tube over and the
> steel balls fall much faster through the liquid.  The second tube has "Same
> density, Different size"  and has steel ball bearings 3//8, 3/16 and 1/16 of
> an inch diameter balls, also in mineral oil.  The small balls take quite
> some to get down to the bottom of the overturned tube.   The reason is that
> the surface area of a solid sphere goes up by the square, while it's volume
> and therefore mass goes up by the cube.  The third tube has real stones and
> sediment in it.   Experiment with what you use here; it was nice having some
> really fine sediment that would leave a layer on top if it was allowed to
> sit for ten minutes.   Big particles  lined the bottom, and by picking
> materials of different densities that had different colors, you could get
> some nice layering.
>
> The overall text explained how the size and density of material in a stream
> decides how far downstream it gets carried.  Boulders don't go very far.
>  The finest silt can stay in suspension to make it all the way to the sea.
>
> We did add a leather pad in the back to keep it from being spun at high
> speed.
>
> I might be able to dig up a photo if it would help.
>
> Clifford Wagner
>
> On Aug 18, 2008, at 6:04 PM, Mike Levad wrote:
>
>  ISEN-ASTC-L is a service of the Association of Science-Technology Centers
>> Incorporated, a worldwide network of science museums and related
>> institutions.
>>
>> *****************************************************************************
>>
>> Hey Everybody,
>>
>> We are building a sediment model which consists of a tube with a clear
>> fluid
>> in it and different sized particles. When you turn it over the bigger
>> stuff
>> hits the bottom first and the little stuff stays on top.  I have seen this
>> in a few different places.  Is anybody willing to share what works best
>> for
>> the clear fluid and the sediment particles?
>>
>> Thanks,
>>
>> Mike
>>
>>
>>
>>
>> Mike Levad
>> Lead Exhibit Developer
>> 651-789-4735 (direct)
>> 651-631-2211 xt.735
>> 651-631-0707fax
>> Toll free: 800-433-9599
>> [log in to unmask]
>> www.splitrockstudios.com
>>
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-- 
David L. Smith
Da Vinci Science Center
Allentown, PA
http://www.davinci-center.org

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