<<Steve Pizzey used to say that every interactive exhibit should have a
small
screw that requires regular adjusting, for this very reason.

The idea being that 'exhibit guides', or whatever that centre calls them,
whip a screwdriver out of a breast pocket whenever they walk past it. In
that way they inevitably present the least intimidating form of contact
with whichever member of the public happens to be standing near it at the
time>>

Love the idea!!!  Anything to make the "guide" less intimidating.  It is
much easier for a nervous or shy guide to answer questions that are asked
of them, than it is to have to approach a member of the public and start a
conversation.

Robert Krampf
Science Education Company
http://members.aol.com/krampf/home.html