Thanks. I forgot about science!

In Florence, there's also the Da Vinci museum - it's not huge, but there are working builds of some of Da Vinci's designs, many of which you can play with a bit.

There is also La Specola (in Oltrarno, south of the Pitti Palace, so stop at Pitti Gola on the way back) if you're into natural history - it's essentially a palazzo with 30+ rooms filled with specimens. Some are plaster/models, but the majority are real. I think the Medici family built that collection over the years, and when you look at it, you wonder how the hell that could even be legal today

The Galileo museum is very good. It's jam packed with things. I will say that the last time we went, although every piece was labeled in English and Italian, that the English text lost a lot of the details found in the Italian description. Something might be labeled as "Glass Medicine Vial" and then have a paragraph in Italian telling you more about it. It didn't seem to detract for my wife (who can't read Italian), but once I noticed the disparity I started translating and it was better for both of us. There is also a small hands-on area where you can demo some models.

I'm sure there's more that I'm just not thinking of.