ISEN-ASTC-L is a service of the Association of Science-Technology Centers
Incorporated, a worldwide network of science museums and related institutions.
*****************************************************************************

Thank you to everyone who responded to my question about wind tunnel  
shapes.

Cricket, our wind tunnel (which is a prototype made out of  
fiberglassed cardboard and built mostly by a local engineer and a few  
other volunteers) has a sled in the test chamber that holds the  
shapes.  The sled is attached to a string which comes out of the  
bottom of the test chamber.  When the shape is put on the sled and  
the wind turned on, the sled gets pushed back.  The visitor then  
pulls the string to move the shape through the wind.  The visitor can  
feel the resistance of different shapes, but can also attach a simple  
spring scale to the string and pull with the spring scale to measure  
the resistance.  We wanted something very hands-on and kinesthetic,  
not just a number that showed up on a digital readout.  Now we just  
need a sponsor so we can build the real thing!

Thanks,
Anna

On Jun 19, 2009, at 12:57 PM, Cricket Brooks wrote:

> ISEN-ASTC-L is a service of the Association of Science-Technology  
> Centers
> Incorporated, a worldwide network of science museums and related  
> institutions.
> ********************************************************************** 
> *******
>
> Hi all -
>
> I think the model cars at Science City worked great, and I'd be  
> happy to
> expand on Jeff's description of how we fabricated them - they were not
> usable on the exhibit floor directly out of the box - if anybody's
> interested.  I could probably unearth some photos of the process we  
> used.
>
> A nice perk of the model cars is that we could order various  
> recognizable
> makes/models at a consistent scale (I think we used 1:18) for direct
> comparison: Hummer vs VW Bug vs Corvette, etc.  I'm sure a Prius  
> would be
> available now as well.
>
> Two thoughts I'll add:
>
> - the models were fairly expensive to replace on a regular basis,  
> so we
> intentionally made them look less attractive and hence less likely  
> to walk
> away.  Grey primer coat painted over the unsanded hardcoat made  
> them look
> very plain, with the added benefit that they definitely called to mind
> prototype clay models.   Also, keeping them all the same color  
> forced the
> user to focus on the differences in shape over cosmetic appearance.
>
> - our wind tunnel at Science City was set up so that the air blew  
> the model
> cars and made them move, versus being set up so that the visitor  
> moved the
> cars into the wind.  This had what I thought was an unfortunate  
> effect:  the
> more wind-resistant, less efficient models moved FURTHER than the more
> efficient models.  (The air passed more readily over the Corvette  
> without
> moving it than over the Hummer.) I thought that a visitor would  
> have to
> think pretty hard to make the connection that the car moving  
> further would
> be the one that was less fuel efficient.  Also, the effect of the  
> mass of
> the vehicle on the distance it moved was the opposite of the effect  
> of the
> aerodynamics of its shape.  (The Hummer would have moved even  
> further had it
> been the same shape but lighter).
>
> If I were designing this exhibit from scratch, I think it would be far
> stronger to have the visitor place the model in the same chamber,  
> but then
> have to work via a hand crank or other mechanism to move the  
> vehicle into
> the airflow.
>
> That way, there would be a direct positive correlation between the  
> energy
> needed to move the vehicle and its wind resistance - the message we  
> were
> trying to convey.   Plus, the lesson would be felt kinesthetically,  
> not just
> visually.
>
> Just my $0.02.
>
> Cricket Brooks
>

Anna Grace
Exhibit Coordinator
[log in to unmask]

===========
Our mission: "We engage people in science experiences that touch all  
our lives."

Explorit Science Center
P.O. Box 1288
Davis, CA 95617
530.756.0191
fax 530.756.1227
www.explorit.org
www.explorit.org/news

Think It. Try It.  Explorit.
===========

**This e-mail is intended only for the personal and confidential use  
of the recipient(s) named above.  If you have received this  
communication in error, please contact the sender by reply email.


***********************************************************************
For information about the Association of Science-Technology Centers and the Informal Science Education Network please visit www.astc.org.

Check out the latest case studies and reviews on ExhibitFiles at www.exhibitfiles.org.

The ISEN-ASTC-L email list is powered by LISTSERVR software from L-Soft. To learn more, visit
http://www.lsoft.com/LISTSERV-powered.html.

To remove your e-mail address from the ISEN-ASTC-L list, send the
message  SIGNOFF ISEN-ASTC-L in the BODY of a message to
[log in to unmask]