Technological/scientific sightseeing suggestions?

[Tor Lillqvist <tml novell com>]

I arrive in Stuttgart already on the 27th, in the morning, and intend
to spend at least one day doing general touristy things. I'm wondering
whether there are any interesting sites in Stuttgart or vicinity
related to the history of science and technology? Places where
prominent old natural philosophers worked? Civil engineering
landmarks? Old mines? Anything of special interest to a railfan? I
know about the Mercedes-Benz and Porsche museums, but cars aren't
really my cup of tea.

Which is more interesting for a daytrip, Esslingen (where the GUADEC
tour goes) or Tübingen? Or even Heidelberg (which is only 40 min by
train from Stuttgart)?

--tml