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

Hello Chris,

I built this exhibit when I worked at the New York Hall of Science over 
20 years ago now - hard for me to believe I'm getting to be (though not 
quite) - an old timer.

So, you are forcing me to disturb a few cobwebs, but this is what I 
remember....

I built up my blocks from polyethylene foam. At the time I could get it 
in 3 lb, 6 lb and 9 lb densities. I believe I went with 6 lb, because it 
was firm enough, but not too firm or too heavy for little people to more 
around. It came in 2" thick slabs. I had a plastics shop laminate 7 
slabs (14" thick) then we cut them into the needed shapes. At the time 
only white foam was available so I had these blocks covered in 'Cordura' 
(pack cloth) which was removable using Velcro. Now, it is available in 
black and maybe some other colors.

It made a strong arch. I have a picture of about 6 kids standing on it. 
It could easily handle 300lbs. Because of that I had trouble making the 
abutments strong enough!  They were plywood but covered in the same foam 
in case of falls. I also surrounded the thing in spongy carpet tiles at 
least 6' in all directions.

This was a great exhibit for several reasons in my mind. It was 
difficult to build by yourself so it encouraged cooperation. It started 
as a pile of stuff and ended in a nice construction, which you could 
walk across and then break apart. Really nice.

Joe Ruggiero
www.TheExhibitGuys.com



Chris Sancomb wrote:

> ISEN-ASTC-L is a service of the Association of Science-Technology Centers
> Incorporated, a worldwide network of science museums and related 
> institutions.
> ***************************************************************************** 
>
>
> We are redesigning a keystone arch activity that many of you are  
> probably familiar with. Children build a keystone arch out of five 
> blocks that they then can walk over. We had it made once, and the 
> blocks, although nice and met most of our criteria were to soft and 
> compress when a child of around 50 pounds sits on them. I am looking 
> for other materials that will be lightweight enough for small children 
> to handle, soft enough to not knock someone out when they sail across 
> a room, yet sturdy enough to work under compression. Any suggestions 
> would be helpful. Thanks
>


***********************************************************************
More information about the Informal Science Education Network and the
Association of Science-Technology Centers may be found at http://www.astc.org.
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]