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Jeff,

Granted, there are several things one can do with this exhibit.  In  
addition to some of what you describe,  the kids at CDM always used to  
blow the air up their shirts, and those with long hair would let it  
stream in the wind,  so we mounted a mirror on the wall nearby so they  
could see themselves.  I might describe it as "somewhat", but not  
"incredibly" rich.  Here is a snip from Chuck Howarth's earlier post:


>  Dupage Children's outside Chicago has another version where kids  
> make their own Bernoulli blowers with PVC pipe, ping pong balls, and  
> a table with multiple ports to plug into for pressurized air.  It's  
> much more open-ended than the original and gives kids a chance to  
> play with a variety of configurations.

I prefer the latter because it is designed to encourage all sorts of  
creative play, not simply allow for it.  The link I posted to Karen  
and Mike's great work with Wind Tubes at PIE is another example.   I'm  
a big fan, if you can pardon the pun.

Tom Nielsen




On May 28, 2009, at 9:13 AM, Jeff Courtman 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 Tom:  The Bernoulli is actually one of my favorites and in fact  
> can be incredibly rich:  Try stacking more than one sphere...slowly  
> move a short ring down over the sphere.....place your hand near one  
> side of the sphere.........tape some short tinsel to several points  
> on the ping pong ball.....
>
> That's the wonderful thing about science center exhibits -- at their  
> best, they are a library of experiences - you may get excited by one  
> thing, I, another.
> 	
>
>  Dupage Children's outside Chicago has another version where kids  
> make their own Bernoulli blowers with PVC pipe, ping pong balls, and  
> a table with multiple ports to plug into for pressurized air.  It's  
> much more open-ended than the original and gives kids a chance to  
> play with a variety of configurations.
>
> On May 28, 2009, at 10:59 AM, Tom Nielsen wrote:
>
>> *This message was transferred with a trial version of  
>> CommuniGate(tm) Pro*
>> ISEN-ASTC-L is a service of the Association of Science-Technology  
>> Centers
>> Incorporated, a worldwide network of science museums and related  
>> institutions.
>> *****************************************************************************
>>
>> Erich,
>>
>> I have found most versions of "Bernoulli Blower"  -- even the  
>> Exploratorium's, when it's placed in a smaller space -- to be too  
>> loud for my taste.  ( I suppose in truth the "modern world" is too  
>> loud for my taste, but what's to be done?)  There is a direct  
>> tradeoff between the CPM and the noise, but other factors are  
>> important too.  The path the air takes as it leaves the blower, and  
>> the aperture where it exits create resonances that shape the  
>> character of the sound.  We had a quite powerful squirrel cage  
>> blower in San Jose, driven by a 230 volt  3 phase induction motor.   
>> Someone discovered (or was brilliant enough to know) that placing a  
>> tennis ball at the aperture magically lowered the noise while only  
>> slightly reducing the height at which the ball flies.  The blower  
>> was also housed in a box lined with acoustic foam, fitted with air  
>> filters  on the intake to avoid sucking in strings and such and a  
>> grill on the outlet to keep coins etc from being dropped in.
>>
>> My preference, to avoid all that bother,  is to forgo the heavier  
>> balls usually used, and go with balloons and a small quiet  
>> ventilating fan.   Yes, you will need to replace the balloons  
>> constantly, but then, beach balls don't last very long either --  
>> and anything more durable takes considerably more air to lift.
>>
>> Lastly, for all that it has been replicated over the years, I don't  
>> think the "Bernoulli Blowers" is a particularly rich exhibit,  
>> compared to the "air play table" you also mention.  The latter  
>> doesn't really need much air to be effective.  Here, for example,  
>> is a wonderful alternative, also from the Exploratorium, that uses  
>> just a window fan:
>>
>> http://www.exploratorium.edu/pie/library/windtubes/index.html
>>
>> quietly,
>>
>> Tom Nielsen
>> www.TheExhibitGuys.com
>>

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