I'm legitimately curious about what makes an exhibit truly "timeless", i.e. as nostalgic for kids who first saw it in 1965 as those who first saw it in 1995. I literally slept in Mathematica once with the Cub Scouts (and in the wave tank room - both had interesting ambient noise), and frankly I think it fits the bill. I didn't care that it was from the '60s, it feels as "old" to me in the same way anything that's been around my whole life is "old". It's a personal frame of reference, not an absolute one.
There's a big difference between a "timeless" thing which feels new to each generation and an "old" thing that's nostalgic only to those who saw it when it was new. I mean, I'm nostalgic for the giant computer climbing structure at the Computer Museum (and frankly for the Computer Museum in general), but that doesn't mean there's a single thing timeless about it. Heck, even the computer exhibit at MoS now feels pretty obsolete. It's been fifteen years since kids have had to go to a museum to play with computers.
I would encourage MoS not to screw up their timeless stuff while dumping the simply "old". Successful museums typically don't only consist of new things, and it's much more expensive to constantly have to update obsolete "cutting-edge" exhibits.
Equilib -- I think you are close to getting it .....
The MOS is globally recognized for the unique mix of:
1) traditional 19th Century type collecting and early 20th Century model making
2) up-to-the-minute interactive displays of the newest concepts
3) unique slices of technology and nature
4) iconic unique working science and technology such as the SEM and Van de Graaff
The keys is that this has all naturally evolved over the past 150+ years and most particularly in its modern incarnation at Science Park
In my experience I can identify several distinct eras both of building and exhibit making:
The early Post WWII Science Park era of the Planetarium, ships Bridge and small models of steam engines and simple machines [ still existing]
Expansion in the East Wing with the New England Life Zones, recreating "Bell's Telephone Lab" cutaway moving V-8 engine, Light house Fresnel Lens, cutaways of Jet Engines, Atomic Pile with radioactive sources [natural and man-made]
The West Wing -- Mathematica is born -- Theatre of Electricity goes Live -- working Steam Engine; Big Dig [still a bit left]
Red wing arrives -- Mugar Omni, New Lobby, New Traveling Exhibit Gallery -- Planetarium Theatre and lobby re-do
Today everything has to be relevant to everyday life -- we celebrate diversity -- we've done away with "right answers" focusing on process and everything is Green [e.g. waterless urinals]
After the bulk of the $200 M is spent mostly within the existing footprint -- the MOS will still be here -- but it will be once again be renewed and re-purposed into the Natural -- featuring the 'Hall of Human Life", Charles [New Lobby] and Built -- featuring [What is Engineering and Technology] -- and perhaps unfortunately -- some of today's old favorites will disappear in the dust of history